6533b85cfe1ef96bd12bd3a9
RESEARCH PRODUCT
Unraveling materials Berry curvature and Chern numbers from real-time evolution of Bloch states
Shunsuke A. SatoNoejung ParkNoejung ParkJeongwoo KimDongbin ShinHannes HübenerUmberto De GiovanniniAngel RubioAngel Rubiosubject
Berry curvatureFOS: Physical sciencesSpin Hall effectquantum spin Hall effect02 engineering and technologyElectronic structure01 natural sciencesQuantumSettore FIS/03 - Fisica Della MateriaTheoretical physicsQuantum spin Hall effectMesoscale and Nanoscale Physics (cond-mat.mes-hall)0103 physical sciencesTime-dependent density functional theory010306 general physicsSpin (physics)QuantumTopological insulatorPhysicstopological insulatorCondensed Matter - Materials ScienceMultidisciplinaryCondensed Matter - Mesoscale and Nanoscale PhysicsPhysicsTime evolutionMaterials Science (cond-mat.mtrl-sci)Observable021001 nanoscience & nanotechnologytime-dependent density functional theoryTopological insulatorPhysical SciencesBerry connection and curvature0210 nano-technologydescription
Materials can be classified by the topological character of their electronic structure and, in this perspective, global attributes immune to local deformations have been discussed in terms of Berry curvature and Chern numbers. Except for instructional simple models, linear response theories have been ubiquitously employed in calculations of topological properties of real materials. Here we propose a completely different and versatile approach to get the topological characteristics of materials by calculating physical observables from the real-time evolving Bloch states: the cell-averaged current density reveals the anomalous velocities whose integration leads to the conductivity quantum. Results for prototypical cases are shown, including a spin-frozen valley-Hall and a quantum anomalous Hall insulator. The advantage of this method is best illustrated by the example of a quantum spin Hall insulator: the quantized spin Hall conductivity is straightforwardly obtained irrespective of the non-Abelian nature in its Berry curvature. Moreover, the method can be extended to the description of real observables in non-equilibrium states of topological materials.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2019-01-01 |