Light-Induced Nonthermal Phase Transition to the Topological Crystalline Insulator State in SnSe

Abstract

Femtosecond pulses have been used to reveal hidden broken symmetry states and induce transitions to metastable states. However, these states are mostly transient and disappear after laser removal. Photoinduced phase transitions towards crystalline metastable states with a change of topological order are rare and difficult to predict and realize experimentally. Here, by using constrained density functional perturbation theory and accounting for light-induced quantum anharmonicity, we show that ultra-fast lasers can permanently transform the topologically-trivial orthorhombic structure of SnSe into the topological crystalline insulating rocksalt phase via a first-order non-thermal phase transition. We describe the reaction path and evaluate the critical fluence and the possible decay channels after photoexcitation. Our simulations of the photoexcited structural and vibrational properties are in excellent agreement with recent pump-probe data in the intermediate fluence regime below the transition with an error on the curvature of the quantum free energy of the photoexcited state that is smaller than 2%.

17 pages, 4 figures, The data underlying this study are openly available in Zenodo at https://doi.org/10.5281/zenodo.8413390

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• Topological Crystalline Insulators
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• Quasiparticle band structures and thermoelectric transport properties of p-type SnSe
• Phonon anharmonicity and negative thermal expansion in SnSe
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• Finding merit in dividing neighbors
• Determination of nonthermal bonding origin of a novel photoexcited lattice instability in SnSe

Cited by in corpus (6)

• Photo-induced electronic and spin topological phase transitions in monolayer bismuth
• Large photo-induced tuning of ferroelectricity in sliding ferroelectrics
• Ultrafast Photo-induced Phase Change in SnSe
• Expanded stability of layered SnSe-PbSe alloys and evidence of displacive phase transformation from rocksalt in heteroepitaxial thin films
• Research on topological materials using ultrafast spectroscopy
• Light-Induced Transient Polarization Reversal in Rhombohedrally Stacked Bilayer Transition Metal Dichalcogenides via an Electronic Mechanism