Spin-Triplet Topological Superconductors

by Prof. Guo-qing Zheng (Okayama University)

Thursday 11 Sept 2025, 10:30 → 11:30 Asia/Shanghai

Tsung-Dao Lee Institute/N4F-N400 - meeting room (Tsung-Dao Lee Institute)

Host: Prof. Vadim Grinenko 

Venue: TDLI Meeting Room N400

Tencent meeting link:  https://meeting.tencent.com/dm/X4BqOxSeAW9o   Meeting ID: 497226917, no password

 

Abstract:

A metal, such as lead, feeling no electrical resistance below a critical temperature Tc, is called a superconductor. In most superconductors including those used in medical equipment MRI-CT, electrons form pairs with anti-parallel spins. Such superconducting state is called spin-singlet state. Two electrons can also form a pair with parallel spins to enter a spin-triplet state. Spin-triplet superconductivity is a rather rare quantum phenomenon, and its physics is much less known compared to the spin-singlet counterpart. The spin-triplet state is fascinating from topological perspectives in particular, as such novel superconductors can host Majorana bound states that can be used in fault-tolerant quantum computing. Mathematically, a spin-triplet state with odd-parity wave function is topologically nontrivial. 

In this seminar, I will introduce our recent results on I will present our recent results on two spin-triplet superconductors, namely, the doped-topological insulator CuxBi2Se3 [1] and strongly-correlated electron system K2Cr3As3 (Tc =6.5 K) [2], with an emphasis on the novel aspects arising from two-component Eu order parameter, such as multiple phases [2-4] and coupling of the order parameter to crystal lattice (phonon) [5,6].

 

References:

[1] K. Matano, M. Kriener, K. Segawa, Y. Ando, G.-q. Zheng, Nature Physics 12, 852 (2016).

[2] J. Yang, J. Luo, C. Yi, Y. Shi, Y. Zhou, and G.-q. Zheng, Science Advances 7, eabl4432 (2021).

[3] T. Kawai, C. G. Wang, Y. Kandori, Y. Honoki, K. Matano, T.Kambe, and G.-q. Zheng, Nat. Commun. 11, 235 (2020).

[4] S. Ogawa, Y. Inada, S. Kawasaki, and G.-q. Zheng, to be submitted.

[5] M. Yokoyama, H. Nishigaki, S. Ogawa, S. Nita, H. Shiokawa, K. Matano, and G.-q. Zheng, Phys. Rev. B 107, L100505 (2023).

[6] K. Matano, S. Takayanagi , K. Ito, S. Nita, M. Yokoyama, M. Mihaescu , H. Nakao, and G.-q. Zheng, Phys. Rev. Lett. 135, 086001 (2025).