Enhanced Dirac node separation in strained Cd3As2 topological semimetal

TL;DR

This study shows that applying strain to Cd3As2 topological semimetals significantly increases Dirac node separation, enabling tunable topological properties for potential technological applications.

Contribution

The paper demonstrates strain-induced enhancement of Dirac node separation in Cd3As2, combining experimental and theoretical methods to reveal strain as a tuning parameter for topological features.

Findings

Giant enhancement of Dirac node separation by nearly 4 times

Strain strengthens topological band inversion

Experimental and theoretical analysis confirms strain effects

Abstract

In topological semimetals, nodes appear at symmetry points in the Brillouin zone as a result of band inversion, and yield quasi-relativistic massless fermions at low energies. Cd3As2 is a three-dimensional topological semimetal that hosts two Dirac cones responsible for a variety of quantum phenomena. In this work, we demonstrate the strain tuning of the Dirac nodes of Cd3As2 through a combination of magnetooptical infrared spectroscopy and high-resolution X-ray diffraction studies performed on epitaxial films. In these thin films, we observe a giant enhancement of the node separation in momentum space by close to a factor of 4. A combination of experimental measurements and theoretical modelling allows relate the origin of this enhancement to a strengthening of the topological band inversion driven by lattice strain. Our results demonstrate how strain can be used as a knob to tune the topological properties of semimetals and to potentially enhance their performance and response for various applications.