"Single-hole wave function in two dimensions: A case study of the doped Mott insulator"

Shuai Chen: Qing-Rui Wang, Yang Qi, D. N. Sheng, and Zheng-Yu Weng; Physical Review B, 05/17/19.

Additional Authors: Qing-Rui Wang, Yang Qi, D. N. Sheng, and Zheng-Yu Weng

Abstract:

We study a ground-state ansatz for the single-hole-doped tJ model in two dimensions via a variational Monte Carlo method. Such a single-hole wave function possesses finite angular momenta generated by hidden spin currents, which give rise to a novel ground-state degeneracy in agreement with recent exact diagonalization (ED) and density matrix renormalization group (DMRG) results. We further show that the wave function can be decomposed into a quasiparticle component and an incoherent momentum distribution in excellent agreement with the DMRG results up to an 8×8 lattice. Such a two-component structure indicates the breakdown of Landau’s one-to-one correspondence principle, and in particular, the quasiparticle spectral weight vanishes by a power law in the large sample size limit. By contrast, turning off the phase string induced by the hole hopping in the so-called σ⋅tJ model, a conventional Bloch-wave wave function with a finite quasiparticle spectral weight can be recovered, also in agreement with the ED and DMRG results. The present study shows that a singular effect already takes place in the single-hole-doped Mott insulator, by which the bare hole is turned into a non-Landau quasiparticle with translational-symmetry breaking. Generalizations to pairing and finite doping are briefly discussed.