Bicircular light tuning of magnetic symmetry and topology in Dirac semimetal Cd$_3$As$_2$

TL;DR

This paper demonstrates how bicircular light can be used to dynamically control magnetic symmetries and topological phases in the Dirac semimetal Cd$_3$As$_2$, enabling transitions to Weyl and topological crystalline insulator phases.

Contribution

It introduces a novel Floquet engineering approach using bicircular light to manipulate magnetic and topological properties in Dirac semimetals, with detailed theoretical predictions for Cd$_3$As$_2$.

Findings

BCL induces a transition to a magnetic Weyl semimetal phase.

Strain combined with BCL leads to a magnetic topological crystalline insulator.

Surface Dirac states are protected by a twofold rotation and time-reversal symmetry.

Abstract

We show that Floquet engineering using bicircular light (BCL) is a versatile way to control magnetic symmetries and topology in materials. The electric field of BCL, which is a superposition of two circularly polarized light waves with frequencies that are integer multiples of each other, traces out a rose pattern in the polarization plane that can be chosen to break selective symmetries, including spatial inversion. Using a realistic low-energy model, we theoretically demonstrate that the three-dimensional Dirac semimetal Cd$_3$As$_2$ is a promising platform for BCL Floquet engineering. Without strain, BCL irradiation induces a transition to a non-centrosymmetric magnetic Weyl semimetal phase with tunable energy separation between the Weyl nodes. In the presence of strain, we predict the emergence of a magnetic topological crystalline insulator with exotic unpinned surface Dirac states that are protected by a combination of twofold rotation and time-reversal $(2')$ and can be controlled by light.