Dipole control of Rashba spin splitting in a type-II Sb/InSe van der Waals heterostructure

Abstract

InSe monolayer, belonging to group III–VI chalcogenide family, has shown promising performance in the realm of spintronic. Nevertheless, the out-of-plane mirror symmetry in InSe monolayer constrains the electrons' degrees of freedom, and this will confine its spin-related applications. Herein, we construct Sb/InSe van der Waals heterostructure to extend the electronic and spintronic properties of InSe. The density functional theory is utilized to verify the tunable electronic properties and Rashba spin splitting (RSS) of Sb/InSe heterostructure. According to the obtained results, the Sb/InSe heterostructure can be considered as a direct band gap semiconductor with typical type-II band alignment, where the electrons and holes are localized in the InSe and Sb layers, respectively. The RSS is recognized at conduction band minimum around Γ point in Sb/InSe, which is induced by the spontaneous internal electric field with electric dipole moment of 0.016 e Å from Sb to InSe. The vertical strain, in-plane strain, and external electric field are employed to modulate the strength of RSS. The Rashba coefficient and dipole moment exhibit the similar variation tendency, suggesting the strength of RSS depends on the magnitude of dipole moment. The controllable RSS makes Sb/InSe heterostructure become an appropriate candidate material for spintronic devices.

Tunable spin-orbit coupling in two-dimensional InSe

“…In addition to the crystalline and the electrostatically induced z → −z asymmetry, few-layer InSe is a material sensitive to interfacial effects due to its limited thickness. Such effects may have an impact in the SOC strength of multilayer InSe and must therefore be taken into consideration 50 . The same two InSe-hBN configurations used for the analysis of interfacial effects in bilayer InSe shown in Table II (configuration 1 and 2) were also used for the calculation of the interface-induced SOC in multilayer InSe as their contribution in the absence of an external electrostatic potential is only dependent on the encapsulating substrates and on the film thickness.…”

“…In addition to the above-discussed effects, mirror symmetry breaking may be caused by the encapsulation environment 50 coupling on the Se orbitals in the outer top/bottom sublayers of the crystal. This asymmetry may be due to the difference between the encapsulating materials, or even due to a different orientation of the top/bottom encapsulating layers of the same compound, e.g., hexagonal boron nitride (hBN).…”

The tunable interface charge transfer by polarization in two dimensional polar Al2O3/MoSO heterostructures

“…Usually, the situation is that one layer gets electrons and another layer loses electrons. Previous research studies 24–86 on 2D vdWs semiconductor heterostructures with type-II band alignment are listed in Table 1. Some of them have been proved theoretically to be Z-scheme photocatalysts for water-splitting.…”

“…Actually, the charge redistribution or interface charge transfer (in the second stage) of 2D heterostructures under extra electric field and stress has been researched. 24–29 Under increasing extra electric field, more electrons flow from one layer to another layer. In addition, by changing the direction of the extra electric field, the direction of interface transfer charge also reverses.…”

Theoretical perspective on the electronic structure and optoelectronic properties of type-II SiC/CrS2 van der Waals heterostructure with high carrier mobilities

“…Coincidentally, the intrinsic zero band gap of graphene [6,7] limits its practical applications in logic electronic and optoelectronic devices. Hence, enormous efforts are involved to modify the electronic structure and optical characteristic of 2D materials [8][9][10][11][12][13][14][15][16][17][18][19][20], such as defects, electric field, strain, vertically stacked van der Waals heterostructure (vdWHs), etc.…”