Giant spin-valley polarization and multiple Hall effect in functionalized bismuth monolayers

Journal Article · Fri Aug 24 00:00:00 EDT 2018 · npj Quantum Materials

DOI:https://doi.org/10.1038/s41535-018-0113-4· OSTI ID:1465242

Zhou, Tong ; Zhang, Jiayong; Jiang, Hua; Žutić, Igor; Yang, Zhongqin

Abstract Valleytronic materials, characterized by local extrema (valleys) in their bands, and topological insulators have separately attracted great interest recently. However, the interplay between valleytronic and topological properties in one single system, likely to enable important unexplored phenomena and applications, has been largely overlooked so far. Here, by combining a tight-binding model with first-principles calculations, we find the large-band-gap quantum spin Hall effects (QSHEs) and valley Hall effects appear simultaneously in the bismuth monolayers decorated with hydrogen/halogen elements, denoted as Bi ₂ XY (X, Y = H, F, Cl, Br, or I). A staggered exchange field is introduced into the Bi ₂ XY monolayers by transition-metal atom (Cr, Mo, or W) doping or LaFeO ₃ magnetic substrates, which together with the strong spin-orbit coupling of bismuth atoms generates a time-reversal-symmetry-broken QSHE and a huge valley splitting (up to 513 meV) in the system. With gate control, QSHE and anomalous charge, spin, valley Hall effects can be observed in the single system. These predicted multiple and exotic Hall effects, associated with various degrees of freedom of electrons, could enable applications of the functionalized bismuth monolayers in electronics, spintronics, and valleytronics.

• Sponsoring Organization: USDOE
• OSTI ID: 1465242
• Journal Information: npj Quantum Materials, Journal Name: npj Quantum Materials Vol. 3 Journal Issue: 1; ISSN 2397-4648
• Publisher: Nature Publishing Group
• Country of Publication: United Kingdom
• Language: English