Mott glass phase in a diluted bilayer Heisenberg quantum antiferromagnet

Abstract

We use quantum Monte Carlo simulations to study a dimer-diluted $S=1/2$ Heisenberg model on a bilayer square lattice with intralayer interaction $J_1$ and interlayer interaction $J_2$. Below the classical percolation threshold $p_c$, the system has three phases reachable by tuning the interaction ratio $g=J_2/J_1$: a N$\acute{e}$el ordered phase, a gapless quantum glass phase, and a gapped quantum paramagnetic phase. We present the ground-state phase diagram in the plane of dilution $p$ and interaction ratio $g$. The quantum glass phase is certified to be of the gapless Mott glass type, having a uniform susceptibility vanishing at zero temperature $T$ and following a stretched exponential form at $T>0$; ${\chi }_u\sim \exp (-b/T^{\alpha })$ with $\alpha <1$. At the phase transition point from N$\acute{e}$el ordered to Mott glass, we find that the critical exponents are different from those of the clean system described by the standard $O(3)$ universality class in 2+1 dimensions.

6 pages, 4 figures, presented at XXVI IUPAP Conference on Computational Physics (CCP2014)

References in corpus (3)

• Quantum-criticality and percolation in dimer-diluted 2D antiferromagnets
• Anomalous quantum glass of bosons in a random potential in two dimensions
• Criticality and Mott-glass phase in a disordered 2D quantum spin systems

Cited by in corpus (1)

• Quantum-critical scaling properties of the two-dimensional random-singlet state