Floquet theory of photoinduced topological phase transitions in the organic salt $\alpha$-(BEDT-TTF)$_2$I$_3$ irradiated with elliptically polarized light

TL;DR

This paper theoretically explores how elliptically polarized light can induce various topological phases in the organic salt $ ext{α}$(BEDT-TTF)$_2$I$_3$, revealing rich nonequilibrium phases and expanding potential materials for optical topological control.

Contribution

It provides a Floquet analysis of photoinduced topological phase transitions in $ ext{α}$(BEDT-TTF)$_2$I$_3$, identifying new nonequilibrium steady phases and broadening the scope of materials for optical manipulation.

Findings

Identification of Floquet Chern insulator, semimetal, and normal insulator phases.

Rich phase diagrams showing diverse nonequilibrium steady states.

Demonstration of optical control over topological electronic states.

Abstract

We theoretically investigate possible photoinduced topological phase transitions in the organic salt $\alpha$-(BEDT-TTF)$_2$I$_3$, which possesses a pair of inclined massless Dirac-cone bands between the conduction and valence bands under uniaxial pressure. The Floquet analyses of a driven tight-binding model for this material reveal rich photoinduced variations of band structures, Chern numbers, and Hall conductivities under irradiation with elliptically polarized light. The obtained phase diagrams contain a variety of nonequilibrium steady phases, e.g., the Floquet Chern insulator, Floquet semimetal, and Floquet normal insulator phases. This work widens a scope of target materials for research on photoinduced topological phase transitions and contributes to development of research on the optical manipulations of electronic states in matters.