Crystallization of the resonating valence bond liquid as vortex condensation

by Arnaud Ralko, Michel Ferrero, Federico Becca, Dmitri Ivanov, and Frederic Mila

This paper is mainly a numerical study of a model that has been a subject of many papers during the last decade, the quantum dimer model on the triangular lattice. As Moessner and Sondhi showed in 2001, this model contains a topological liquid phase in its phase diagram, for the region 0.7< v/t < 1, between a staggered valence bond crystal (v/t > 1) and a complex modulated phase, the \sqrt(13)x\sqrt(13) phase (v/t < 0.7). It was also known from 2001, that the lowest energy topological excitations in the RVB liquid phase, the so-called visons, are gapped at the special point where v/t=1 (together with all the other known excitations of the system). In the paper by Ralko et al., it is shown that the visons become gapless at the transition point between the \sqrt(13)x\sqrt(13) phase and the liquid phase for v/t~0.7. Therefore, they conclude that the transition between the RVB liquid phase and the \sqrt(13)x\sqrt(13) phase is purely topological in origin and probably continuous.

Stephanos Papanikolaou, UIUC