Eur. Phys. J. B 81, 165-177 (2011)
https://doi.org/10.1140/epjb/e2011-10992-5

Quantum spin liquid near Mott transition with fermionized -vortices

Department of Physics, Beijing Normal University, Beijing, 100875, P.R. China

Corresponding author: ^a spkou@mit.edu

Received: 18 December 2010
Revised: 31 March 2011
Published online: 25 May 2011

Abstract

In this paper, we study the non-magnetic insulator state near Mott transition of 2D -flux Hubbard model on square lattice and find that such non-magnetic insulator state is quantum spin liquid state with nodal fermionic excitations – nodal spin liquid (NSL). When there exists small easy-plane anisotropic energy, the ground state becomes Z₂ topological spin liquid (TSL) with full gapped excitations. The mutual-Chern-Simons (MCS) theory is obtained to describe the low energy physics of NSL and TSL.