Doping quantum dimer models on the square lattice

TL;DR

This paper introduces a family of models describing hole motion in a quantum dimer background on the square lattice, revealing various quantum phases and phenomena like holon pairing and hole deconfinement through numerical and analytical methods.

Contribution

It constructs a generalized doped quantum dimer model on the square lattice and maps it to a classical dimer model, providing new insights into phase behavior in doped Mott insulators.

Findings

Identification of quantum phases including VBS and critical liquid phases.

Evidence of holon pairing without phase separation.

Observation of hole deconfinement in the staggered dimer phase.

Abstract

A family of models is proposed to describe the motion of holes in a fluctuating quantum dimer background on the square lattice. Following Castelnovo et al. [Ann. Phys. (NY) 318, 316 (2005)], a generalized Rokhsar-Kivelson Hamiltonian at **finite doping** which can be mapped on a **doped** interacting classical dimer model is constructed. A simple physical extension of this model is also considered. Using numerical computations and simple considerations based on the above exact mapping, we determine the phase diagram of the model showing a number of quantum phases typical of a doped Mott insulator. The two-hole correlation function generically exhibits short-range or long-range algebraic correlations in the solid (columnar) and liquid (critical) phases of the model, respectively. Evidence for an extended region of a doped VBS phase exhibiting holon pairing but **no** phase separation is given. In contrast, we show that hole deconfinement occurs in the staggered dimer phase.