Spin-polarized valley Hall effect in ultrathin silicon nanomembrane via interlayer antiferromagnetic coupling

Abstract

Fundamental understanding of two-dimensional materials has spurred a surge in the search for topological quantum phase associated with the valley degree of freedom (VDOF). We discuss a spinpolarized version to the VDOF in which spin degeneracy is broken by the antiferromagnetic exchange coupling (LAFM) between opposite layers of the quasi-two-dimensional silicon nanomembrane (SiNM). Based on first principles calculations, we found that the LAFM state in SiNM can lead to metal-insulator transition (MIT). The broken degeneracy of spin degree of freedom in this insulating state of ultrathin SiNM may differ for different valleys, so that the SiNM can be exploited to produce the spatially separated spin and valley currents. We propose that the tunable spin-polarized valley photocurrents can be generated in an experimentally feasible ellipsometry setup. Our work shows promise for the development of spintronic and valleytronic devices compatible with current silicon industry.

All‐Silicon Switchable Magnetoelectric Effect through Interlayer Exchange Coupling

“…The Si A and Si B have three nearest neighbors of Si C leaving one dangling bond for each of them. Therefore, the Si surface is like a low‐buckled silicene under the periodic potential of the bulk silicon substrate, which has a periodicity with respect to the bare monolayer Si(111) of 1×1 lattice . The atomic configuration for each Si surface is in agreement with our previous calculations …”

“…periodicity with respectt ot he bare monolayer Si(111)o f1 1l attice. [25] The atomicc onfigurationf or each Si ffiffi ffi 3 p surfacei si na greement with our previousc alculations. [19]…”

“…An excellent example is found in transition metal dichalcogenides (TMDs), where the real spin and layer pseudospin is coupled by spin orbit coupling (SOC) . It was demonstrated that the realization of IAEC is difficult and only some progress was reported recently . Consequently it is very intriguing to investigate the ME effect in semiconducting materials through IAEC.…”

“…[ ly. [23][24][25] Consequently it is very intriguing to investigate the ME effect in d 0 semiconducting materials through IAEC.…”

Epitaxial Growth of Honeycomb Monolayer CuSe with Dirac Nodal Line Fermions

“…A slab model of monolayer CuSe on top of Cu(111) surface is used to simulate the interfacial interaction between them by employing a larger supercell of 38.27 Å × 4.25 Å. The five Cu d orbitals and three Se p orbitals are used to construct the maximally localized Wannier function . Phonon dispersion is calculated based on a 6 × 6 supercell in the finite displacement method as implemented in the PHONOPY package …”