Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal

arXiv:2507.17639 · cond-mat.mtrl-sci, cond-mat.mes-hall, physics.app-ph · Submitted 2025-07-23 · Read on arXiv

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Introduction to the show: ident: Quantum Radio. Generated commentary on the latest quantum physics and condensed matter papers.

Kai: Hi, I'm Kai.

Mira: And I'm Mira, here with Lev.

Kai: We're looking at the paper: "Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal".

Mira: Here's the gist of the paper. The gist This study experimentally probes and reveals the behavior of spin-momentum–locked TSSs through spin-pumping measurements in heterostructures composed of ferromagnetic Fe and the topological Dirac semimetal (TDS) α-Sn, demonstrating highly efficient spin-to-charge conversion with an inverse Edelstein length of 3.14 nm at room temperature, the highest value reported at room temperature for ferromagnet / topological material bilayers Sample and Measurement Setup The researchers grew Fe (4 nm) / α-Sn (tSn nm) heterostructures with tSn = 0, 9, 25, 32.5, and 35 nm on InSb (001) substrates by molecular beam epitaxy (MBE) The epitaxial growth of α-Sn thin film layers was confirmed by in situ reflection high-energy electron diffraction (RHEED), which exhibited streaky patterns and twofold surface reconstruction along both the

110: and

110: directions Xray diffraction (XRD) measurements revealed a sharp α-Sn (004) peak with clear Laue fringes, indicating high crystalline quality Frequency-dependent ferromagnetic resonance (FMR) spectroscopy was carried out on Fe (4 nm) / α-Sn (tSn = 0 – 35 nm) / InSb heterostructures at room temperature using a coplanar waveguide and Keysight vector network analyzer (VNA) The frequency dependence of the peak-to-peak linewidth ∆ (see Figure 2b and 2c) is analyzed to rule out the inhomogeneous broadening of the FMR spectrum Damping Constant Evolution The Gilbert damping constant α was estimated as a function of tSn, showing a pronounced increase as the α-Sn layer thickness increases from tSn = 0 nm (0.0024) to tSn = 25 nm (0.0180), followed by a decrease at greater thicknesses This increase in the damping constant with the insertion of-Sn layer indicates that the-Sn layer acts as a spin-absorption layer The thickness dependence of the damping enhancement and the spin-charge conversion signal also suggests that the dominant spin-to-charge conversion mechanism in this system does not occur in the bulk state of α-Sn Spin Accumulation and Conversion Mechanism The theoretical analysis showed that Dirac-cone-like TSS at the top Fe/αSn interface is largely destroyed due to the magnetic proximity effect (MPE) and strong orbital hybridization with the Fe layer Conversely, a gapped TSS is observed at the bottom α-Sn/InSb interface (modeled as the α-Sn/vacuum interface in Figure 3 a as shown by the purple dispersion surrounded by dashed curves in Figure 3 b-d) The gap energy of the TSS decreases as the α-Sn layer thickness increases and becomes zero above 6.8 nm The long-range MPE from Fe is suggested to be the main driver of the gap opening in the bottom TSS at the α-Sn/InSb interface Spin-to-Charge Conversion Efficiency For the sample with tSn = 25 nm, a clear FMR signal was observed at each microwave power, and a dc voltage peak was observed between the two edges of the sample at the FMR field at each microwave power The induced charge current was then calculated from = (−)/2 and the sheet resistance Rsheet as follows From the injected spin current and the induced charge current, we can estimate the inverse Edelstein length as / This value of λIEE is then estimated to be 3.14 nm This result establishes TDS α-Sn as one of the most promising platforms for spin-charge conversion This work provides valuable insights into the interplay between TSS evolution and spin-charge conversion in topological materials interfaced with ferromagnets The findings underscore the critical role of tuning TSS properties under MPE for advancing topological materials in spintronic applications Table S2 Inverse Edelstein length and spin diffusion length in various material structures estimated at room temperature.

Title and authors: Kai: So we're looking at this paper today titled "Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal." It focuses on how to make that spin-charge conversion really efficient when you put a ferromagnet next to a topological material.

Mira: It’s about engineering that interface, specifically looking at how tuning the properties of the topological surface states affects the overall spin-to-charge conversion efficiency.

Lev: From my side, I'm wondering what kind of practical device we're even talking about here since this is all happening at room temperature and we need to consider real hardware constraints.

Kai: Well, what they’re showing is that by changing the thickness of the topological material layer, specifically alpha-Sn on an InSb substrate, they can get a really strong signal. They measured an inverse Edelstein length of three point one four nanometers for the sample with twenty-five nanometers of alpha-Sn <ref:2507.17639#pg2,an inverse Edelstein length of 3.14>.

Mira: That number, three point one four nanometers, is presented as the highest value reported at room temperature for ferromagnet over topological material bilayers in their study "Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal" <ref:2507.17639#pg2> <ref:2507.17639#pg1,Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal>.

Lev: thirty point one four nanometers is a specific number, so we need to think about how that compares to the noise floor we see when you try to build a real device with this kind of material.

Kai: What they did was grow these Fe layer and alpha-Sn layer heterostructures on InSb substrates with thicknesses ranging from zero up to thirty-five nanometers, using molecular beam epitaxy. They used frequency-dependent ferromagnetic resonance spectroscopy to look at the damping constant evolution across all those different thicknesses.

Mira: It’s important that they analyzed that frequency dependence of the peak-to-peak linewidth, which is how they ruled out any simple inhomogeneous broadening issues in the ferromagnetic resonance spectrum <ref:2507.17639#pg2>.

Lev: So if we're talking about actual device fabrication, knowing the damping constant alpha changing with thickness is helpful because it tells us how much spin absorption is happening at the interface.

Kai: Exactly. They found that this damping constant alpha starts very low, around zero point zero zero two four when there's no alpha-Sn layer, then it increases significantly as the alpha-Sn layer gets thicker up to twenty-five nanometers, and then it starts decreasing again at even greater thicknesses <ref:2507.17639#pg3>.

Mira: That increase in the damping constant when you insert the alpha-Sn layer suggests that this extra layer acts like a spin-absorption layer, which is a key physical mechanism they are pointing toward <ref:2507.17639#pg3>.

Lev: So what does that mean for us building things? If the material itself is absorbing spins, that could complicate our efforts to control them with external fields.

Title and authors: Kai: That’s one way to think about it. Now, the theoretical side of this paper looked at what's actually happening at those interfaces when you have a ferromagnet and a topological insulator.

Mira: Theoretically, they found that the Dirac-cone-like topological surface states at the top interface between Fe and alpha-Sn are largely destroyed because of the magnetic proximity effect or MPE and strong orbital hybridization with the Fe layer <ref:2507.17639#pg3>.

Lev: So if those states are destroyed there, how does that explain why they still get such a high conversion efficiency when they use this specific thickness?

Kai: They found something else interesting: at the bottom interface between alpha-Sn and InSb, there's a gapped topological surface state observed <ref:2507.17639#pg3>.

Mira: And they modeled that gapped state, and it showed that the gap energy of this topological surface state actually decreases as the alpha-Sn layer thickness increases, becoming zero above six point eight nanometers <ref:2507.17639#pg3> <ref:2507.17639#pg3>.

Lev: So what drives this gap opening at the bottom interface? Is it just the way these two materials hybridize, or is there something else at play?

Kai: The long-range magnetic proximity effect from the Fe layer seems to be driving that gap opening in that bottom topological surface state at the alpha-Sn and InSb interface <ref:2507.17639#pg3>.

Mira: That’s a big piece of information because it tells us exactly which interaction—the MPE versus just simple hybridization—is responsible for stabilizing the state they are measuring.

Lev: For real hardware, we have to worry about those long-range effects. If the MPE is doing the heavy lifting, that means controlling that interface requires precise control over the magnetic field and layer thickness across a larger area than just what's right at the surface.

Kai: The whole point of this study was to experimentally probe and reveal these behaviors through spin-pumping measurements in these specific heterostructures <ref:2507.17639#pg1>.

Mira: The main implication, according to their summary, is that this work underscores the critical role of tuning those topological surface states under MPE for advancing topological materials in spintronic applications <ref:2507.17639#pg2>.

Lev: So for someone just listening to the show, what does this mean for the future of spin devices? It suggests we might not need bulky spacer layers if we can engineer the thickness right.

Kai: Right, it means that by tuning those properties under MPE, we can advance topological materials in spintronic applications <ref:2507.17639#pg2>.

Mira: And they also showed how to quantify the efficiency, estimating the inverse Edelstein length by using an analytical model and fitting parameters from Table S1 to predict that three point one four nanometer value <ref:2507.17639#pg2> <ref:2507.17639#pg1>.

Title and authors: Lev: Quantifying it like that is what we need for design, but we have to remember those assumptions in their model when trying to translate that into something that runs on a real system.

Kai: The paper suggests this alpha-Sn material is one of the most promising platforms for spin-charge conversion because of these results <ref:2507.17639#pg2>.

Mira: So they’re pointing toward using this specific type of topological Dirac semimetal for next-generation devices that rely on efficient spin-charge interconversion at room temperature.

Lev: I'm curious if we can actually get those three point one four nanometer results reliably translated into a scalable device, or if the material limitations they mentioned still hold true when scaling up <ref:2507.17639#pg1>.

Kai: That’s the next step, figuring out how to make this work in a practical setup rather than just seeing the numbers in a simulation <ref:2507.17639#pg2>.

Mira: So we've seen how tuning TSS properties under MPE leads to high conversion efficiency, but we still have to deal with those interface complexities.

Lev: Exactly. The damping constant evolution and the mechanism identification are important pieces that show us *why* it works, but the engineering reality is what matters most for building a functional device.

Kai: This paper "Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal" gives us a clear picture of how to start tuning these topological materials for spintronics.

Mira: It shows that even with the magnetic proximity effect present, we can still get highly efficient spin-to-charge conversion when we tune the thickness appropriately <ref:2507.17639#pg2>.

Lev: So for our audience, this paper highlights that controlling the interface isn't just about keeping things clean; it’s about using those magnetic interactions to enhance performance.

Kai: The paper provides a lot of data on how much tuning affects things, from the damping constant evolution up to that final inverse Edelstein length value <ref:2507.17639#pg2>.

Mira: It really lays out the link between material structure, the proximity effect, and measurable spin-charge conversion efficiency in this system <ref:2507.17639#pg3>.

Lev: Before we move on, I just want to emphasize that while these results are exciting for the material science side, we still have to address those limitations they mentioned about bulk spin diffusion lengths being short in heavy element topological materials <ref:2507.17639#pg3>.

Kai: That’s a fair point, and that limitation is definitely something we need to keep in mind as we look at larger systems.

Mira: So, for now, this work on "Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal" gives us a solid experimental baseline for what's achievable at room temperature.

Lev: And that baseline helps us define the targets for the next generation of error correction and device design based on these topological properties <ref:2507.17639#pg2>.

The paper's summary: Kai: So, this paper is looking at how you can tune that topological material, specifically alpha-Sn on an InSb substrate, to get a really strong spin-to-charge conversion signal when you put a ferromagnet next to it.

Mira: Right. They’re showing that by changing the thickness of the alpha-Sn layer, they can get this measurable change in efficiency.

Kai: What they actually did was grow these Fe and alpha-Sn heterostructures on InSb substrates with thicknesses ranging from zero up to thirty-five nanometers using molecular beam epitaxy.

Mira: And they used frequency-dependent ferromagnetic resonance spectroscopy to check the damping constant evolution across all those different thicknesses.

Kai: They found that this damping constant, alpha, starts really low when there's no alpha-Sn layer, around zero point zero zero two four when it's just Fe on InSb.

Mira: Then it goes up significantly as the alpha-Sn layer gets thicker, peaking around twenty-five nanometers at a value of zero point zero one eight.

Kai: That increase in alpha suggests that this extra layer acts like a spin-absorption layer, which is what they’re pointing toward when they discuss the mechanism.

Mira: And theoretically, they found that the Dirac cone-like surface states at the top interface between Fe and alpha-Sn get destroyed because of magnetic proximity effect and strong orbital hybridization with the Fe layer.

Kai: That makes sense if those states are destroyed there, so how do you still get such a high conversion efficiency when you use that twenty-five nanometer thickness?

Mira: They looked at the bottom interface between alpha-Sn and InSb, where they saw a gapped topological surface state.

Kai: And they modeled that gap energy showing it actually decreases as the alpha-Sn layer gets thicker, becoming zero above six point eight nanometers.

Mira: The long-range magnetic proximity effect from the Fe layer seems to be driving that gap opening in that bottom topological surface state at the alpha-Sn and InSb interface.

Kai: That’s a big piece of information because it tells us exactly which interaction—the proximity effect versus just simple hybridization—is responsible for stabilizing the state they are measuring.

Mira: So, for someone just listening to this show, this paper shows that you can use the magnetic proximity effect to actively tune the topological surface states and get a measurable spin-to-charge conversion signal.

Kai: They also showed how to quantify it, estimating the inverse Edelstein length by using an analytical model and fitting parameters from Table S1 to predict that three point one four nanometer value for the sample with twenty-five nanometers of alpha-Sn.

Mira: So they’re pointing toward using this specific type of topological Dirac semimetal as one of the most promising platforms for spin-charge conversion because of these results at room temperature.

Kai: It really lays out the link between material structure, the proximity effect, and measurable spin-to-charge conversion efficiency in this system.

Mira: Before we look at what they did next, I want to mention that while these results are exciting for the material science side, they also flag a limitation about bulk spin diffusion lengths being short in heavy element topological materials.

Kai: That’s fair, and that limitation is something we need to keep in mind as we look at larger systems.

Mira: So for now, this work gives us a solid experimental baseline for what's achievable at room temperature in this setup.

Kai: And that baseline helps us define the targets for the next generation of error correction and device design based on these topological properties.

The paper's improvements: Kai: So, we’re looking at what they suggest to make this whole setup even better, moving beyond just showing that it works at room temperature with this specific material combination.

Mira: Right. They’re pointing toward optimizing the interface control so we can get better performance than what they achieved in their original experiment.

Kai: The paper suggests that the key is really focusing on tuning those topological surface states under magnetic proximity effect, which means we need to control the thickness very precisely.

Mira: Exactly. They found that the damping constant evolution and the mechanism identification were important because they show us *why* it works, not just *that* it works.

Kai: Specifically, they emphasize that by tuning those properties under MPE, you can advance topological materials in spintronic applications.

Mira: And they showed how to quantify the efficiency by using an analytical model and fitting parameters from Table S1 to predict that three point one four nanometer value for the sample with twenty-five nanometers of alpha-Sn.

Kai: That’s a good thing because quantifying it like that is what we need for design, but we have to remember those assumptions in their model when trying to translate that into something that runs on a real system.

Mira: They also showed how to screen candidate topological materials by comparing predicted performance metrics, like estimating the spin diffusion length lambdaSn and inverse Edelstein length lambdaIEE for different structures.

Kai: So they’re pointing toward using this specific type of topological Dirac semimetal as one of the most promising platforms because it has these tunable properties.

Mira: It really lays out the link between material structure, the proximity effect, and measurable spin-to-charge conversion efficiency in this system.

Kai: The paper provides a lot of data on how much tuning affects things, from the damping constant evolution up to that final inverse Edelstein length value.

Mira: It really shows that even with the magnetic proximity effect present, we can still get highly efficient spin-to-charge conversion when you tune the thickness appropriately.

Kai: So for our audience, this paper highlights that controlling the interface isn't just about keeping things clean; it’s about using those magnetic interactions to enhance performance.

Mira: It really lays out the link between material structure, the proximity effect, and measurable spin-to-charge conversion efficiency in this system.

Kai: Before we look at what they did next, I want to mention that while these results are exciting for the material science side, they also flag a limitation about bulk spin diffusion lengths being short in heavy element topological materials.

Mira: That’s fair, and that limitation is something we need to keep in mind as we look at larger systems.

Kai: So for now, this work on "Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal" gives us a solid experimental baseline for what's achievable at room temperature in this setup.

Mira: And that baseline helps us define the targets for the next generation of error correction and device design based on these topological properties.

Conclusion: Kai: So, to wrap up, this paper on "Giant Spin-to-Charge Conversion by Tailoring Magnetically Proximitized Topological Dirac Semimetal" shows how you can actively tune the interface properties of Fe and alpha-Sn to get a really strong spin signal at room temperature.

Mira: Right. It boils down to engineering the proximity effect, specifically controlling that thickness on the alpha-Sn layer to get that high efficiency number, three point one four nanometers for instance.

Kai: They proved that by tuning those properties under magnetic proximity effect, you can advance topological materials in spintronic applications because you’re getting a measurable spin-charge conversion signal where you didn't expect it before.

Mira: And they showed how to quantify it by using an analytical model and fitting parameters from Table S1 to predict that three point one four nanometer value for the sample with twenty-five nanometers of alpha-Sn.

Kai: So they’re pointing toward using this specific type of topological Dirac semimetal as one of the most promising platforms because it has these tunable properties.

Mira: It really lays out the link between material structure, the proximity effect, and measurable spin-to-charge conversion efficiency in this system.

Kai: The paper provides a lot of data on how much tuning affects things, from the damping constant evolution up to that final inverse Edelstein length value.

Mira: It really shows that even with the magnetic proximity effect present, you can still get highly efficient spin-to-charge conversion when you tune the thickness appropriately.

Kai: So for our audience, this paper highlights that controlling the interface isn't just about keeping things clean; it’s about using those magnetic interactions to enhance performance.

Mira: It really lays out the link between material structure, the proximity effect, and measurable spin-to-charge conversion efficiency in this system.

Kai: Before we get out of here, Lev has something to say about what this actually means for building real hardware.

Lev: From my side, I have to stress that while these results are exciting for the material science side, they also flag a limitation about bulk spin diffusion lengths being short in heavy element topological materials.

Mira: That’s fair, and that limitation is something we need to keep in mind as we look at larger systems.

Lev: And that baseline helps us define the targets for the next generation of error correction and device design based on these topological properties.

Department of Electrical Engineering and Information Systems, The University of Tokyo · Center for Spintronics Research Network, The University of Tokyo Department of Applied Physics, Graduate School of Engineering, Tohoku University Department of Information Science and Technology, Graduate School of Science and Engineering, Yamagata University National Institute of Technology Fukushima College Japan Institute for Nano Quantum Information Electronics The University of Tokyo

cond-mat.mtrl-sci, cond-mat.mes-hall, physics.app-ph

Submitted: 2025-07-23

Updated: 2026-10-20

DOI: 10.1103/jg51-9xf7

License: http://creativecommons.org/licenses/by/4.0/

Importance score: 79/100

The gist: The gist This study experimentally probes and reveals the behavior of spin-momentum–locked TSSs through spin-pumping measurements in heterostructures composed of ferromagnetic Fe and the

Key concepts

Spin-Momentum Locking: This phenomenon occurs in topological materials where the spin of an electron is intrinsically linked to its direction of motion (momentum). When this happens, applying a charge current generates a transverse spin current, which is the foundation for efficient spin-to-charge conversion.
Inverse Edelstein Length ($\lambda_{IEE}$): This parameter quantifies how effectively a spin current can be converted into an electrical charge current. A larger inverse Edelstein length means that a given amount of injected spin will produce a stronger measurable voltage or charge flow, indicating high efficiency in the conversion process.
Magnetic Proximity Effect (MPE): This effect describes how the magnetic properties of an adjacent material, like Fe, influence the electronic structure of an adjacent topological material. In this study, MPE is crucial because it modifies the Dirac cone states at interfaces, leading to changes in the material's gap and spin transport characteristics.
Topological Dirac Semimetal ($\alpha$-Sn): $\alpha$-Sn is a specific type of topological material exhibiting unique electronic properties, including Dirac cones. These cones allow for highly efficient spin transport. The study focuses on how the thickness of this material affects its gap and spin-charge conversion capabilities when coupled with a ferromagnet.

Terminology

Proximity Effect — 1× in this paper · explained in 2 episodes

Summary

The gist

This study experimentally probes and reveals the behavior of spin-momentum–locked TSSs through spin-pumping measurements in heterostructures composed of ferromagnetic Fe and the topological Dirac semimetal (TDS) α-Sn, demonstrating highly efficient spin-to-charge conversion with an inverse Edelstein length of 3.14 nm at room temperature, the highest value reported at room temperature for ferromagnet / topological material bilayers

Sample and Measurement Setup

The researchers grew Fe (4 nm) / α-Sn (tSn nm) heterostructures with tSn = 0, 9, 25, 32.5, and 35 nm on InSb (001) substrates by molecular beam epitaxy (MBE) The epitaxial growth of α-Sn thin film layers was confirmed by in situ reflection high-energy electron diffraction (RHEED), which exhibited streaky patterns and twofold surface reconstruction along both the [110] and [110] directions Xray diffraction (XRD) measurements revealed a sharp α-Sn (004) peak with clear Laue fringes, indicating high crystalline quality Frequency-dependent ferromagnetic resonance (FMR) spectroscopy was carried out on Fe (4 nm) / α-Sn (tSn = 0 – 35 nm) / InSb heterostructures at room temperature using a coplanar waveguide and Keysight vector network analyzer (VNA) The frequency dependence of the peak-to-peak linewidth ∆ (see Figure 2b and 2c) is analyzed to rule out the inhomogeneous broadening of the FMR spectrum

Damping Constant Evolution

The Gilbert damping constant α was estimated as a function of tSn, showing a pronounced increase as the α-Sn layer thickness increases from tSn = 0 nm (0.0024) to tSn = 25 nm (0.0180), followed by a decrease at greater thicknesses This increase in the damping constant with the insertion of-Sn layer indicates that the-Sn layer acts as a spin-absorption layer The thickness dependence of the damping enhancement and the spin-charge conversion signal also suggests that the dominant spin-to-charge conversion mechanism in this system does not occur in the bulk state of α-Sn

Spin Accumulation and Conversion Mechanism

The theoretical analysis showed that Dirac-cone-like TSS at the top Fe/αSn interface is largely destroyed due to the magnetic proximity effect (MPE) and strong orbital hybridization with the Fe layer Conversely, a gapped TSS is observed at the bottom α-Sn/InSb interface (modeled as the α-Sn/vacuum interface in Figure 3 a as shown by the purple dispersion surrounded by dashed curves in Figure 3 b-d) The gap energy of the TSS decreases as the α-Sn layer thickness increases and becomes zero above 6.8 nm The long-range MPE from Fe is suggested to be the main driver of the gap opening in the bottom TSS at the α-Sn/InSb interface

Spin-to-Charge Conversion Efficiency

For the sample with tSn = 25 nm, a clear FMR signal was observed at each microwave power, and a dc voltage peak was observed between the two edges of the sample at the FMR field at each microwave power The induced charge current was then calculated from = (−)/2 and the sheet resistance Rsheet as follows From the injected spin current and the induced charge current, we can estimate the inverse Edelstein length as / This value of λIEE is then estimated to be 3.14 nm This result establishes TDS α-Sn as one of the most promising platforms for spin-charge conversion

Conclusion

This work provides valuable insights into the interplay between TSS evolution and spin-charge conversion in topological materials interfaced with ferromagnets The findings underscore the critical role of tuning TSS properties under MPE for advancing topological materials in spintronic applications

Table S2

Inverse Edelstein length and spin diffusion length in various material structures estimated at room temperature.

Improvements for AI systems

Increased Predictive Accuracy for Spintronic Device Performance: The improved AI system can accurately predict how Gilbert damping constant alpha evolves as a function of topological material thickness (tSn), specifically identifying the pronounced peak at tSn = 25 nm based on experimental spin-pumping measurements, which is crucial for optimizing device design.
Quantification of Spin-Charge Conversion Efficiency: The system can estimate the inverse Edelstein length by using the derived analytical model in Equation (9) and fitting parameters from Table S1, allowing it to predict the highest value reported at room temperature for ferromagnet / topological material bilayers, such as the estimated 3.14 nm.
Mechanism Identification under Magnetic Proximity Effect (MPE): The improved AI can differentiate between theoretical models by analyzing the damping enhancement dependence, specifically determining whether the gap opening in the bottom TSS is driven by hybridization between the states on the opposing surfaces of α-Sn or the long-range MPE from Fe, based on fitting results in Figure 4b.
Material Selection for High Efficiency: The system can rapidly screen candidate topological materials by comparing their predicted performance metrics, such as estimating the spin diffusion length (λSn) and inverse Edelstein length (λIEE) for different structures, allowing it to identify TDS α-Sn as a promising platform over others like Bi2Se3.

Abstract

The role of magnetic proximity on topological surface states (TSSs) and spin-to-charge conversion efficiency is studied in Fe/topological Dirac semimetal α-Sn heterostructures. As α-Sn thickness increases (9-38 nm), the damping constant of Fe peaks at 25 nm and then decreases. Theoretical modeling links this to long-range magnetic proximity effects (MPE) that suppress TSSs at the Fe/ α-Sn interface while opening an exchange gap at the opposite interface. At 25 nm, we achieve an inverse Edelstein length of-3.1 plus or minus 1.0 nm, one of the highest values at room temperature, highlighting MPE's importance in spintronics.

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Key concepts

Terminology

Summary

Improvements for AI systems

Abstract

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