Topological states in condensed matter systems and gauge theories

2015 Fiscal Year Final Research Report

• Project/Area Number: 23540437
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Mathematical physics/Fundamental condensed matter physics
• Research Institution: Hirosaki University (2012-2015); The University of Tokyo (2011)
• Principal Investigator: GORYO Jun 弘前大学, 理工学研究科, 准教授 (70365013)
• Project Period (FY): 2011-04-28 – 2016-03-31
• Keywords: トポロジー / 超伝導 / Kane-Mele模型 / スピン軌道相互作用

Outline of Final Research Achievements

We investigated the topological states in condensed matter systems. We focused on the Kane-Mele model defined on the honeycomb lattice system. We took into account the electron-electron correlation in this model by using the Stratonovich-Hubbard method, in which we introduced an auxiliary field behaving like a gauge field. We obtained the effective action to integrate out the auxiliary field and found a non-trivial electromagnetic response. We also discussed Cooperon condensation in the Kane-Mele model and classified the pairing symmetry of Cooperon wave function by using the point group. We pointed out that the recent discovered superconductor SrPtAs can be regarded as the superconducting state of doped Kane-Mele model. The most plausible pairing symmetry is chiral d-wave which supports the chiral surface state, and we investigated the transport phenomena at the surface of the system. Due to the spin-orbit coupling, the surface state carries not only charge but also spin.

Free Research Field

理論凝縮系物理学