Circular photocurrents in centrosymmetric semiconductors with hidden spin polarization

• Published in: Nature communications Vol. 15; no. 1; pp. 9036 - 8
• Main Authors: Wang, Kexin, Zhang, Butian, Yan, Chengyu, Du, Luojun, Wang, Shun
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.10.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/119/1001; 639/624/1075/401; 639/766/1130/2798; Chalcogenides; Circular polarization; Electric currents; Electromagnetism; Feasibility studies; Hall effect; Humanities and Social Sciences; Light beams; Molybdenum disulfide; multidisciplinary; Multilayers; Phase transitions; Photoelectric effect; Photoelectric emission; Polarization; Polarization (spin alignment); Polarized light; Science; Science (multidisciplinary); Semiconductors; Symmetry; Transition metal compounds; Wavelengths
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-53425-9

Centrosymmetric materials with site inversion asymmetries possess hidden spin polarization, which remains challenging to be converted into spin currents because the global inversion symmetry is still conserved. This study demonstrates the spin-polarized circular photocurrents in centrosymmetric transition metal dichalcogenide semiconductors at normal incidence without applying electric bias. The global inversion symmetry is broken by using a spatially-varying circularly polarized light beam, which could generate spin gradient owing to the hidden spin polarization. The dependence of the circular photocurrents on electrode configuration, illumination position, and beam spot size indicates an emergence of circulating electric current under spatially inhomogeneous light, which is associated with the deflection of spin-polarized current through the inverse spin Hall effect. The circular photocurrents is subsequently utilized to probe the spin polarization and the inverse spin Hall effect under different excitation wavelengths and temperatures. The results of this study demonstrate the feasibility of using centrosymmetric materials with hidden spin polarization and non-vanishing Berry curvature for spintronic device applications. The authors report the generation of circular photocurrents from multilayer 2H-phase transition metal dichalcogenides, including MoTe 2 , MoS 2 , and WSe 2 , which is attributed to the manifestation of hidden spin polarization and inverse spin Hall effect.