Time: 09:30am (UTC/GMT+08:00, Beijing/Shanghai), Dec. 16 (Wedn.), 2020

Online Meeting Room (zoom.com): Click here to join the meeting

Meeting ID: 989 4399 6803

Password: 123456

Speaker: Dr. Cheng Peng (Stanford)

Abstract:

Pair-density wave (PDW) is a novel superconducting (SC) state in which the SC order parameter varies periodically in real space in such a way that its spatial average vanishes. Broad interest in PDW state has emerged due to the direct observations in recent experiments of underdoped cuprate superconductors. Moreover, it has long been proposed that superconductivity can emerge in doping quantum spin liquids (QSLs). Whether the PDW state can be induced by doping certain QSL still remains an open question. We study the effects of doping the Kitaev model on the honeycomb lattice where the spins interact via the bond-directional interaction JK, which is known to have a quantum spin liquid as its exact ground state. The effect of hole doping is studied within the t-JK model on a three-leg cylinder using density-matrix renormalization group. Upon light doping, we find that the ground state of the system has quasi-long-range charge-density-wave correlations but short-range single-particle correlations. The dominant pairing channel is the even-parity superconducting pair-pair correlations with d-wave-like symmetry, which oscillate in sign as a function of separation with a period equal to that of the spin-density wave and two times the charge-density wave. Although these correlations fall rapidly (possibly exponentially) at long distances, this is never-the-less the first example where a pair-density wave is the strongest SC order on a bipartite lattice. Our results may be relevant to Na2IrO3 and α-RuCl3 upon doping.

Ref. [1] C. Peng, Y.-F. Jiang, T. P. Devereaux and H.-C. Jiang. arXiv, 2008.03858.

About The Speaker:

Currently a Postdoctoral Scholar in SLAC and Stanford University. Her interests focus on simulating strongly correlated electron systems with density matrix renormalization groups (DMRG) and tensor network, the studying systems including high temperature superconductor related Hubbard model, doping spin liquid related t-J-like model, and spin model with strong geometry frustration. She participates in developing the open source DMRG algorithm library GraceQ/MPS2, which is available on https://github.com/gracequantum/mps2