Light-induced hidden odd-frequency order in a model for A$_3$C$_{60}$

TL;DR

This paper demonstrates that laser excitation can induce a hidden odd-frequency orbital order in a model for A$_3$C$_{60}$, revealing a nonthermal phase transition and expanding the understanding of light-controlled electronic phases.

Contribution

It introduces a theoretical model showing how photo-doping can create a hidden odd-frequency order in a multi-orbital system, which does not have an equilibrium counterpart.

Findings

Photo-doping induces a hidden odd-frequency orbital order.

Laser excitation can melt magnetic order nonthermally.

Hidden phase exhibits broken orbital symmetry without equilibrium analog.

Abstract

Laser driving in systems with competing or coupled electronic orders can lead to the enhancement of orders, or even to the appearance of hidden phases without an equilibrium analogue. Here we consider a model for A$_3$C$_{60}$ which exhibits a unique interplay between conventional and odd-frequency (or composite) orders. In particular, we show that photo-doping of the antiferromagnetic Mott insulating phase, as realized in Cs$_3$C$_{60}$, results in a paramagnetic gapped state with broken orbital symmetry. This hidden phase, which does not exist under equilibrium conditions, can be interpreted as an odd-frequency orbital-ordered state, and is conceptually related to the equilibrium Jahn-Teller metal in more weakly correlated compounds. Our study demonstrates the appearance of pure odd-frequency order via the nonthermal melting of magnetic order, and provides an interesting example of nonequilibrium control of electronic orders in a multi-orbital system.