Manipulating Weyl quasiparticles by orbital-selective photoexcitation in WTe2

Meng-Xue Guan,En Wang,Jia-Tao Sun,Sheng Meng,Pei-Wei You

doi:10.1038/s41467-021-22056-9

Abstract

Optical control of structural and electronic properties of Weyl semimetals allows development of switchable and dissipationless topological devices at the ultrafast scale. An unexpected orbital-selective photoexcitation in type-II Weyl material WTe2 is reported under linearly polarized light (LPL), inducing striking transitions among several topologically-distinct phases mediated by effective electron-phonon couplings. The symmetry features of atomic orbitals comprising the Weyl bands result in asymmetric electronic transitions near the Weyl points, and in turn a switchable interlayer shear motion with respect to linear light polarization, when a near-infrared laser pulse is applied. Consequently, not only annihilation of Weyl quasiparticle pairs, but also increasing separation of Weyl points can be achieved, complementing existing experimental observations. In this work, we provide a new perspective on manipulating the Weyl node singularity and coherent control of electron and lattice quantum dynamics simultaneously.

Highlights

Optical control of structural and electronic properties of Weyl semimetals allows development of switchable and dissipationless topological devices at the ultrafast scale
Three-dimensional Weyl semimetals (WSMs) are novel topological phases of matter, in which the chiral Weyl nodes can be viewed as pseudo-magnetic monopoles in momentum space and the magnetic charge is determined by chirality[1,2,3,4,5,6,7]
The main results of this work established a connection between the unique orbital features around the Weyl nodes and the polarizationswitchable interlayer displacement, which is significantly different from the works that appeared recently in literature

Summary

Introduction

Optical control of structural and electronic properties of Weyl semimetals allows development of switchable and dissipationless topological devices at the ultrafast scale. The symmetry features of atomic orbitals comprising the Weyl bands result in asymmetric electronic transitions near the Weyl points, and in turn a switchable interlayer shear motion with respect to linear light polarization, when a near-infrared laser pulse is applied. 1234567890():,; Three-dimensional Weyl semimetals (WSMs) are novel topological phases of matter, in which the chiral Weyl nodes can be viewed as pseudo-magnetic monopoles in momentum space and the magnetic charge is determined by chirality[1,2,3,4,5,6,7] These magnetic monopoles have direct effects on the motion of electrons, providing an ideal platform to explore the nonlinear optoelectronic responses that related to topology in gapless materials[8,9]. The effective electron–phonon interactions drive switchable interlayer shear displacements, providing an ultrafast way for modulating topological properties, e.g., annihilation or increasing separation of Weyl nodes

Methods

Results

Conclusion