Supersolidity, entropy, and frustration: t-t '-V model of hard-core bosons on the triangular lattice
|Titre||Supersolidity, entropy, and frustration: t-t '-V model of hard-core bosons on the triangular lattice|
|Type de publication||Journal Article|
|Auteurs||Hassan SR, de Medici L, Tremblay A-MS|
|Journal||Physical Review B|
|Année de publication||2007|
We study the properties of t-t(')-V model of hard-core bosons on the triangular lattice that can be realized in optical lattices. By mapping to the spin-1/2 XXZ model in a field, we determine the phase diagram of the t-V model where the supersolid characterized by the ordering pattern (x,x,-2x(')) ("ferrimagnetic" or SS A) is a ground state for chemical potential mu>3V. By turning on either temperature or t(') at half filling (mu=3V), we find a first order transition from SS A to the elusive supersolid characterized by the (x,-x,0) ordering pattern ("antiferromagnetic" or SS C). In addition, we find a large region where a superfluid phase becomes a solid upon increasing temperature at fixed chemical potential. This is an analog of the Pomeranchuk effect driven by the large entropic effects associated with geometric frustration on the triangular lattice.