Electrical control of the orbital degrees in 2D systems with broken inversion symmetry

Sayantika BHOWAL

Electrical manipulation of the spin moments, e.g., in a spin Hall effect, is at the heart of the spintronic devices with the advantage of faster processing, higher information density, and low power consumption. Recently, an analogous orbital-degrees-driven effect, viz., the orbital Hall effect, has gained a lot of attention, in which an applied electric field generates a transverse orbital current. The fundamental nature of the orbital Hall effect, its large magnitude, and no dependence on the spin-orbit interaction drive the interest in this field. These also vastly increase the possible phase space of candidate materials for orbitronic applications, compared to spintronics, for encoding information. While the effect occurs for both inversion symmetric and asymmetric systems, the electrical manipulation of the orbital degrees becomes particularly interesting in systems with broken inversion symmetry where intrinsic orbital moments, crucial to the desired effects, are present in the Brillouin zone of the system even in presence of time-reversal symmetry. In my talk, I will discuss the origin of the orbital Hall effect1,2, its connection to the well-known “valley Hall effect”3, and “spin Hall effect”1,2, and the electric current induced orbital magnetization4 in the prototype two-dimensional systems with broken inversion symmetry, such as transition metal dichalcogenides and gapped graphene.

[1] S. Bhowal and S. Satpathy, Phys. Rev. B (Rapid) 101, 121112 (R) (2020)
[2] S. Bhowal and S. Satpathy, Phys. Rev. B 102, 035409 (2020)
[3] S. Bhowal and G. Vignale, Phys. Rev. B 103, 195309 (2021)
[4] S. Bhowal and S. Satpathy, Phys. Rev. B (Rapid) 102, 201403(R) (2020)