Band splitting with vanishing spin polarizations in noncentrosymmetric crystals

Abstract

The Dresselhaus and Rashba effects are well-known phenomena in solid-state physics, in which spin-orbit coupling (SOC) splits spin-up and spin-down energy bands of nonmagnetic non-centrosymmetric crystals. Here, we discover a new phenomenon, dubbed as band splitting with vanishing spin polarizations (BSVSP), in which, as usual, SOC splits the energy bands in nonmagnetic non-centrosymmetric systems; surprisingly, however, both split bands show no net spin polarization along certain high-symmetry lines in the Brillouin zone. In order to rationalize this phenomenon, we propose a new classification of point groups into pseudo-polar and non-pseudo-polar groups. By means of first-principles simulations, we demonstrate that BSVSP can take place in both symmorphic (e.g., bulk GaAs) and non-symmorphic systems (e.g., two dimensional ferroelectric SnTe). Furthermore, we propose a novel linear magnetoelectric coupling in reciprocal space, which could be employed to tune the spin polarization with an external electric field. The BSVSP effect and its manipulation could therefore pave a new way to novel spintronic devices.

References in corpus (4)

• Emergence of the persistent spin helix in semiconductor quantum wells
• All-electric all-semiconductor spin field effect transistors
• Rashba-Dresselhaus spin-splitting in the bulk ferroelectric oxide BiAlO${}_3$
• Direct determination of spin orbit interaction coefficients and realization of the persistent spin helix symmetry

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• Tunable Electronic Properties and Large Rashba Splittings Found in Few-Layer Bi${}_2$Se${}_3$/PtSe${}_2$ Van der Waals Heterostructures
• Diversity of Radial Spin Textures in Chiral Materials
• Two-dimensional Topological Semimetals Protected by Symmorphic Symmetries
• Understanding spin textures in PT-broken systems through universal symmetry-constrained rules
• Matter with apparent and hidden spin physics