Issue 6, 2020

Emergence of a spin-valley Dirac semimetal in a strained group-VA monolayer

Abstract

The combination of Dirac and Valley physics in one single-layer system is a very interesting topic and has received widespread attention in materials science and condensed matter physics. Using density-functional theoretical calculations, we predict that a two-dimensional (2D) cyanided group-VA monolayer, MAs(CN)2 (M = Sb, Bi), can turn into the spin-valley Dirac point (svDP) state under external strains. In sharp contrast to the symmetry protected 2D Dirac semimetal (DSM), the Dirac Fermions in svDP materials are spin non-degenerate due to strong spin-splitting under SOC. Remarkably, the Dirac fermions in inequivalent valleys can host opposite Berry curvature and spin moment, leading to the Dirac spin-valley Hall effect with dissipationless transport. We also find that the svDP of MAs(CN)2 is a critical state of topological phase transition between the trivial and nontrivial states. An effective tight-binding model is used to unveil the physics of svDP and topological phase transition under strain. These results will provide a route towards the integration of spin-valley indexes in 2D Dirac materials and design multipurpose and controllable devices in valleytronics.

Graphical abstract: Emergence of a spin-valley Dirac semimetal in a strained group-VA monolayer

Article information

Article type
Paper
Submitted
08 Nov 2019
Accepted
06 Jan 2020
First published
03 Feb 2020

Nanoscale, 2020,12, 3950-3957

Emergence of a spin-valley Dirac semimetal in a strained group-VA monolayer

M. Zhang, S. Zhang, P. Wang and C. Zhang, Nanoscale, 2020, 12, 3950 DOI: 10.1039/C9NR09545D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements