Competing supersolids of Bose-Bose mixtures in a triangular lattice

F. Trousselet (1) , P. Rueda-Fonseca (2) , A. Ralko (1)

1 NEEL - TMC - Théorie de la Matière Condensée
2 SP2M - UMR 9002 - Service de Physique des Matériaux et Microstructures

We study the ground state properties of a frustrated two-species mixture of hard-core bosons on a triangular lattice, as a function of tunable amplitudes for tunnelling and interactions. By combining three different methods, a self-consistent cluster mean-field, exact diagonalizations and effective theories, we unravel a very rich and complex phase diagram. More specifically, we discuss the existence of three original mixture supersolids: (i) a commensurate with frozen densities and supersolidity in spin degrees of freedom, in a regime of strong interspecies interactions; and (ii) when this interaction is weaker, two mutually competing incommensurate supersolids. Finally, we show how these phases can be stabilized by a quantum fluctuation enhancement of peculiar insulating parent states.

Domaines: Physique [physics]

F. Trousselet, P. Rueda-Fonseca, A. Ralko. Competing supersolids of Bose-Bose mixtures in a triangular lattice. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2014, 89 (8), pp.085104. ⟨10.1103/PhysRevB.89.085104⟩. ⟨hal-01331231⟩