「Nematic superconductivity in topological materials」
Anne de Visser 氏

Oct 21, 2019

日本物理学会北海道支部講演会

講演題目：　Nematic superconductivity in topological materials
講　師　：　Anne de Visser 氏
　　　　　　Van der Waals-Zeeman Institute, University of Amsterdam, The Netherland
日　時　：　2019年10月21日 (月) 16:30 - 17:30
場　所　：　北海道大学理学部5号館5-206
要　旨　：
Topological insulators have generated a wide research interest, because they offer access to novel quantum states with unprecedented properties. Most interestingly, the concept of topological insulators can be transferred to superconductors, where the superconducting gap plays the role of the band gap of the insulator. Topological superconductors are predicted to have an exotic Cooper-pair state in the bulk and gapless Andreev bound states at the surface (Majorana modes), and therefore offer new, challenging routes to test theories of unconventional superconductivity. In this presentation I will focus on the recent developments in superconducting Bi2Se3-based crystals, where field-angle dependent measurements of the transport, thermal and magnetic properties have revealed a spontaneous breaking of the rotational symmetry [1,2,3]. The rotational symmetry breaking in the macroscopic superconducting properties is explained in terms of nematic superconductivity, that is associated with a two-component superconducting order parameter (Eu representation) [4]. The experimental results provide solid evidence for unconventional superconductivity with an odd-parity spin-polarized triplet Cooper-pair state (Δ4-pairing),that was recently proposed for rhombohedral topological superconductors [5].

[1] Y. Pan et al., Sci. Rep. 6, 28632 (2016).
[2] S. Yonezawa et al., Nature Phys. 13, 123 (2017).
[3] T. Asaba et al., Phys. Rev. X 7, 011009 (2017).
[4] J. Venderbos et al., Phys. Rev. B 94, 180504R (2016).
[5] L. Fu, Phys. Rev. B 90, 100509R (2014).


世話人　網塚　浩

（北海道大学大学院理学研究院　物理学部門）