Direct observation of spin-polarized bulk bands in an inversion-symmetric semiconductor

DOI: 10.1038/nphys3105

Authors: J. M. Riley (University of St Andrews) , F. Mazzola (Norwegian University of Science and Technology) , M. Dendzik (Aarhus University) , M. Michiardi (Aarhus University) , T. Takayama (University of Tokyo) , L. Bawden (University of St Andrews) , C. Granerød (Norwegian University of Science and Technology) , M. Leandersson (Lund University) , T. Balasubramanian (Lund University) , M. Hoesch (Diamond Light Source) , T. K. Kim (Diamond Light Source) , H. Takagi (University of Tokyo) , W. Meevasana (Suranaree University of Technology) , Ph. Hoffmann (Aarhus University) , M. S. Bahramy (The University of Tokyo) , J. W. Wells (Norwegian University of Science and Technology) , P. D. C. King (University of St Andrews)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature Physics , VOL 10 (11) , PAGES 835–839

State: Published (Approved)
Published: October 2014
Diamond Proposal Number(s): 9427 , 9500

Abstract: Methods to generate spin-polarized electronic states in non-magnetic solids are strongly desired to enable all-electrical manipulation of electron spins for new quantum devices. This is generally accepted to require breaking global structural inversion symmetry. In contrast, here we report the observation from spin- and angle-resolved photoemission spectroscopy of spin-polarized bulk states in the centrosymmetric transition-metal dichalcogenide WSe2. Mediated by a lack of inversion symmetry in constituent structural units of the bulk crystal where the electronic states are localized we show how spin splittings up to ∼0.5 eV result, with a spin texture that is strongly modulated in both real and momentum space. Through this, our study provides direct experimental evidence for a putative locking of the spin with the layer and valley pseudospins in transition-metal dichalcogenides of key importance for using these compounds in proposed valleytronic devices.

Diamond Keywords: Semiconductors

Subject Areas: Physics, Materials


Instruments: I05-ARPES

Other Facilities: I3 at MAX-III

Added On: 22/10/2014 21:24

Discipline Tags:

Quantum Materials Physics Hard condensed matter - structures Electronics Materials Science

Technical Tags:

Spectroscopy Angle Resolved Photoemission Spectroscopy (ARPES)