Topological aspect and transport property in multi-band spin-triplet chiral p-wave superconductor Sr2RuO4

International Conference on Strongly Correlated Electron Systems 2014

Imai, Yoshiki^1 ; Wakabayashi, Katsunori^2 ; Sigrist, Manfred^3

Department of Physics, Saitama University, Saitama, Japan^1

International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan^2

Theoretische Physik, ETH-Honggerberg, Zürich, Switzerland^3

关键词: Lifshitz transition;    Spin-triplet chiral p-wave superconductors;    Superconducting phase;    Superconducting state;    Surface conditions;    Tight binding model;    Topological number;    Topological properties;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012132/pdf
DOI  :  10.1088/1742-6596/592/1/012132

来源: IOP

【 摘 要 】

Considering the superconductor Sr2RuO4, we analyze a three-band tight-binding model with one hole-like and two electron-like Fermi surfaces corresponding to the α, β and γ bands of Sr2RuO4by means of a self-consistent Bogoliubov-de Gennes approach for ribbonshaped system to investigate topological properties and edge states. In the superconducting phase two types of gapless edge states can be identified, one of which displays an almost flat dispersion at zero energy, while the other, originating from the γ band, has a linear dispersion and constitutes a genuine chiral edge states. Not only a charge current appears at the edges but also a spin current due to the multi-band effect in the superconducting phase. In particular, the chiral edge state from the γ band is closely tied to topological properties, and the chiral p-wave superconducting states are characterized by an integer topological number, the so-called Chern number. We show that the γ band is close to a Lifshitz transition. Since the sign of the Chern number may be very sensitive to the surface condition, we consider the effect of the surface reconstruction observed in Sr2RuO4on the topological property and show the possibility of the hole-like Fermi surface at the surface.