First-Order Character and Observable Signatures of Topological Quantum Phase Transitions
Publikation: Beitrag in Fachzeitschrift › Forschungsartikel › Beigetragen › Begutachtung
Beitragende
Abstract
Topological quantum phase transitions are characterized by changes in global topological invariants. These invariants classify many-body systems beyond the conventional paradigm of local order parameters describing spontaneous symmetry breaking. For noninteracting electrons, it is well understood that such transitions are continuous and always accompanied by a gap closing in the energy spectrum, given that the symmetries protecting the topological phase are maintained. Here, we demonstrate that a sufficiently strong electron-electron interaction can fundamentally change the situation: we discover a topological quantum phase transition of first-order character in the genuine thermodynamic sense that occurs without a gap closing. Our theoretical study reveals the existence of a quantum critical endpoint associated with an orbital instability on the transition line between a 2D topological insulator and a trivial band insulator. Remarkably, this phenomenon entails unambiguous signatures related to the orbital occupations that can be detected experimentally.
Details
Originalsprache | Englisch |
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Aufsatznummer | 185701 |
Fachzeitschrift | Physical review letters |
Jahrgang | 114 |
Ausgabenummer | 18 |
Publikationsstatus | Veröffentlicht - 8 Mai 2015 |
Peer-Review-Status | Ja |
Extern publiziert | Ja |