title: Temperature-driven topological quantum phase transitions in a phase-change material Ge2Sb2Te5.
abstract: The Ge2Sb2Te5is a phase-change material widely used in optical memory devices and is a leading candidate for next generation non-volatile random access memory devices which are key elements of various electronics and portable systems. Despite the compound is under intense investigation its electronic structure is currently not fully understood. The present work sheds new light on the electronic structure of the Ge2Sb2Te5crystalline phases. We demonstrate by predicting from first-principles calculations that stable crystal structures of Ge2Sb2Te5possess different topological quantum phases: a topological insulator phase is realized in low-temperature structure and Weyl semimetal phase is a characteristic of the high-temperature structure. Since the structural phase transitions are caused by the temperature the switching between different topologically non-trivial phases can be driven by variation of the temperature. The obtained results reveal the rich physics of the Ge2Sb2Te5compound and open previously unexplored possibility for spintronics applications of this material, substantially expanding its application potential.
authors.affiliation: Institute of Strength Physics and Materials Science, 634055, Tomsk, Russia.|Tomsk State University, 634050 Tomsk, Russia.|Saint Petersburg State University, Saint Petersburg, 198504, Russia.|Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain.
authors.forename: S V
authors.initials: SV
authors.lastname: Eremeev
authors.affiliation: Tomsk State University, 634050 Tomsk, Russia.|Saint Petersburg State University, Saint Petersburg, 198504, Russia.
authors.forename: I P
authors.initials: IP
authors.lastname: Rusinov
authors.affiliation: Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain.|Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM - MPC and Centro Mixto CSIC-UPV/EHU, 20080 San Sebastián/Donostia, Basque Country, Spain.
authors.forename: P M
authors.initials: PM
authors.lastname: Echenique
authors.affiliation: Tomsk State University, 634050 Tomsk, Russia.|Saint Petersburg State University, Saint Petersburg, 198504, Russia.|Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain.|Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM - MPC and Centro Mixto CSIC-UPV/EHU, 20080 San Sebastián/Donostia, Basque Country, Spain.
authors.forename: E V
authors.initials: EV
authors.lastname: Chulkov