Journal article
Spin Hall Conductivity in Bi 1- x Sb x as an Experimental Test of Bulk-Boundary Correspondence
Nano letters, Vol.25(21), pp.8775-8781
05/28/2025
DOI: 10.1021/acs.nanolett.5c01806
PMID: 40387049
Abstract
Bulk-boundary correspondence, a foundational principle underlying the electronic band structure and physical behavior of topological quantum materials, has been rigorously tested in topological systems that involve conserved charge currents. However, it remains unclear whether bulk-boundary correspondence should hold for nonconserved spin currents. We address this unresolved question by using spin-torque ferromagnetic resonance to accurately probe the charge-to-spin conversion efficiency in epitaxial thin films of a canonical topological insulator, Bi
Sb
. We find that the measured effective spin Hall conductivity (SHC) agrees well with tight-binding calculations for the intrinsic SHC of the bulk bands. These results indicate that the strong spin-orbit entanglement of bulk states well below the Fermi energy connects directly to the SHC of surface states in epitaxial Bi
Sb
films interfaced with a metallic ferromagnet. The excellent agreement between theory and experiment affirms the generic value of analyses focused entirely on bulk properties, even for nonconserved topological spin currents.
Details
- Title: Subtitle
- Spin Hall Conductivity in Bi 1- x Sb x as an Experimental Test of Bulk-Boundary Correspondence
- Creators
- Yongxi Ou - Pennsylvania State UniversityWilson Yánez-Parreño - Pennsylvania State UniversityYu-Sheng Huang - Pennsylvania State UniversitySupriya Ghosh - University of Minnesota SystemCüneyt Şahin - University of IowaMax Stanley - Pennsylvania State UniversitySandra Santhosh - Pennsylvania State UniversitySaurav Islam - Pennsylvania State UniversityAnthony Richardella - Pennsylvania State UniversityK Andre Mkhoyan - University of Minnesota SystemMichael E Flatté - University of IowaNitin Samarth - Pennsylvania State University
- Resource Type
- Journal article
- Publication Details
- Nano letters, Vol.25(21), pp.8775-8781
- Publisher
- AMER CHEMICAL SOC
- DOI
- 10.1021/acs.nanolett.5c01806
- PMID
- 40387049
- ISSN
- 1530-6984
- eISSN
- 1530-6992
- Grant note
- Division of Materials Research: DMR-2039351 Penn State Two-Dimensional Crystal Consortium-Materials Innovation Platform (2DCC-MIP) under NSF: DMR-2309431 NSF: DMR-2011839 Penn State MRSEC under NSF: DMR-2011401 NSF through the MRSEC
The authors thank A. Sengupta for providing access to apparatus used in ST-FMR measurements. This project was supported by the Penn State Two-Dimensional Crystal Consortium-Materials Innovation Platform (2DCC-MIP) under NSF Grant No. DMR-2039351 (Y.O., A.R., N.S.). Additional support was provided by SMART/SRC-nCORE/NIST (W.Y., N.S., S.G., A.M.), NSF Grant No. DMR-2309431 (S.G., K.A.M.), and the Penn State MRSEC under NSF Grant No. DMR-2011839 (W.Y., N.S.). Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the NSF through the MRSEC (DMR-2011401).
- Language
- English
- Date published
- 05/28/2025
- Academic Unit
- Electrical and Computer Engineering; Physics and Astronomy
- Record Identifier
- 9984824327302771
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