Piezoelectric Manipulation and Engineering for Layertronics in Two-Dimensional Materials

TL;DR

This paper proposes a theoretical coupling strategy between valleytronics and piezoelectricity in 2D materials, enabling control of anomalous valley Hall and layer Hall effects through strain-induced electric fields, with potential for multifunctional nanodevices.

Contribution

It introduces a novel valley-piezoelectric coupling mechanism in 2D ferrovalley systems, extending the understanding of transport phenomena in valleytronics.

Findings

Strain induces large electric fields in 2D ferrovalley monolayers.

The coupling enables realization of AVHE and LHE in these systems.

Microscopic mechanisms of interlayer AFM states are elucidated.

Abstract

The electronic transport characteristics of two-dimensional (2D) systems have widespread application prospects in the fabrication of multifunctional nanodevices. However, the current research for basic transport phenomena, such as anomalous valley Hall effect (AVHE) and piezoelectric response, is limited to discrete discussion. Here, we theoretically propose a valley-piezoelectricity coupling strategy beyond the existing paradigm to realize AVHE and layer Hall effect (LHE) in ferrovalley (FV) systems, and its essential principle can be extended to general valleytronic materials. Through first-principles calculations, we demonstrate that the large polarized electric field of 2.8*106 (1.67*107) V/m can be induced by 0.1% uniaxial strain in FV 2H-LaHF (1T-LaHF) monolayers. In addition, the microscopic mechanism of interlayer antiferromagnetic (AFM) state of 2H-LaHF bilayer is uncovered by the spin Hamiltonian and super-superexchange (SSE) interaction. Our findings pave the way for new explorations of valley Hall-related effect involving piezoelectricity.