Spinon Fermi surface in a cluster Mott insulator model on a triangular lattice and possible application to 1T-TaS₂

2018/03/31 by Wen-Yu He, Xiao Yan Xu, Gang Chen +2 · 2 citations
Physics and Astronomy · #cond-mat.str-el

paper · pdf · doi:10.1103/physrevlett.121.046401

published as Phys. Rev. Lett. 121, 046401 (2018) · 5+11 pages, 4+13 figures

arxiv created 2018/05/10 · arxiv updated 2018/07/27

Abstract

1T-TaS₂ is a cluster Mott insulator on the triangular lattice with 13 Ta atoms forming a star of David cluster as the unit cell. We derive a two dimensional XXZ spin-1/2 model with four-spin ring exchange term to describe the effective low energy physics of a monolayer 1T-TaS₂, where the effective spin-1/2 degrees of freedom arises from the Kramers degenerate spin-orbital states on each star of David. A large scale density matrix renormalization group simulation is further performed on this effective model and we find a gapless spin liquid phase with spinon Fermi surface at moderate to large strength region of four-spin ring exchange term. All peaks in the static spin structure factor are found to be located on the "2k_F" surface of half-filled spinon on the triangular lattice. Experiments to detect the spinon Fermi surface phase in 1T-TaS₂ are discussed.

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