Light-Driven Topological and Magnetic Phase Transitions in ThinLayer Antiferromagnets

We theoretically study the effect of low-frequency light pulses in resonance withphonons in the topological and magnetically ordered two-septuple layer (2-SL) MnBi2Te4(MBT) and MnSb2Te4(MST). These materials share symmetry properties and anantiferromagnetic ground state in pristine form but present different magnetic exchangeinteractions. In both materials, shear and breathing Raman phonons can be excited vianonlinear interactions with photoexcited infrared phonons using intense laser pulses that can beattained in the current experimental setups. The light-induced transient lattice distortions leadto a change in the sign of the effective interlayer exchange interaction and magnetic orderaccompanied by a topological band transition. Furthermore, we show that moderate antisitedisorder, typically present in MBT and MST samples, can facilitate such an effect. Therefore,our work establishes 2-SL MBT and MST as candidate platforms for achieving non-equilibriummagneto-topological phase transitions

Automated summary

This study theoretically explores the effects of low-frequency light pulses in resonance with phonons in the topological and magnetically ordered two-septuple layer (2-SL) MnBi2Te4 (MBT) and MnSb2Te4 (MST). It is found that transient lattice distortions induced by intense laser pulses can change the sign of the interlayer exchange interaction, leading to magnetic order and topological band transitions. Additionally, moderate antisite disorder can facilitate this effect.