Ultrafast photoinduced phase transition in the antiferromagnetic Dirac semimetal EuAgAs

TL;DR

This study demonstrates a subpicosecond, light-induced phase transition in EuAgAs, a magnetic Dirac semimetal, revealing the potential for ultrafast control of topological states via optical excitation.

Contribution

It reports the first observation of ultrafast photoinduced phase transition in EuAgAs, linking magnetic order to topological state changes using ultrafast spectroscopy.

Findings

Distinct fluence-dependent responses in magnetic states

Evidence of magnetic order-driven topological transition

Potential for ultrafast control of topological phases

Abstract

We report the observation of a light-induced subpicosecond phase transition in the antiferromagnetic Dirac semimetal EuAgAs, achieved through ultrafast optical excitation. Using ultrafast optical spectroscopy, we probe the nonequilibrium carrier dynamics, discovering distinct fluence-dependent responses in the antiferromagnetic and paramagnetic states, and revealing a possible magnetic order-driven transition between different topological states. Our results demonstrate that EuAgAs, with its highly tunable magnetic structure, possibly offers a unique platform for exploring topological phase transitions. These results underscore the potential of ultrashort optical pulses as powerful tools for the real-time control of topological phases, opening pathways for advances in spintronics, quantum computing, and energy-efficient information technologies.