Breakdown of the Bloch-wave behavior for a single hole in a gapped antiferromagnet

TL;DR

This paper investigates how a single doped hole behaves in a gapped antiferromagnetic system, revealing a transition from Bloch wave propagation to a symmetry-broken state linked to phase string effects, using DMRG calculations.

Contribution

It demonstrates a transition in hole behavior in a gapped antiferromagnet driven by phase string entanglement, without closing the spin gap.

Findings

Transition from Bloch wave to symmetry-broken state observed

Connection established between transition and phase string entanglement

Spectral weight distribution reveals the nature of the transition

Abstract

Whether a doped hole propagates as a Bloch wave or not is an important issue of doped Mott physics. Here we examine this problem based on the quasiparticle spectral weight $Z$ distribution, calculated by density matrix renormalization group (DMRG). By tuning the anisotropy of a two-leg $t$-$J$ ladder without closing the background spin gap, the $Z$ distribution unambiguously reveals a transition of the single hole state from a Bloch wave to a novel one with spontaneous translational symmetry breaking. We further establish a direct connection of such a transition with a nonlocal phase string entanglement between the hole and quantum spins, which explains numerical observations.