Title: Inhomogeneous hard-core bosonic mixture with checkerboard supersolid phase: Quantum and thermal phase diagram,
Abstract: We introduce an inhomogeneous bosonic mixture composed of two kinds of
hard-core and semi-hard-core bosons with different nilpotency conditions and
demonstrate that in contrast with the standard hard-core Bose-Hubbard model,
our bosonic mixture with nearest- and next-nearest-neighbor interactions on a
square lattice develops the checkerboard supersolid phase characterized by the
simultaneous superfluid and checkerboard solid orders. Our bosonic mixture is
created from a two-orbital Bose-Hubbard model including two kinds of bosons: a
single-orbital boson and a two-orbital boson. By mapping the bosonic mixture to
an anisotropic inhomogeneous spin model in the presence of a magnetic field, we
study the ground-state phase diagram of the model by means of cluster mean
field theory and linear spin-wave theory and show that various phases such as
solid, superfluid, supersolid, and Mott insulator appear in the phase diagram
of the mixture. Competition between the interactions and magnetic field causes
the mixture to undergo different kinds of first- and second-order phase
transitions. By studying the behavior of the spin-wave excitations, we find the
reasons of all first- and second-order phase transitions. We also obtain the
temperature phase diagram of the system using cluster mean field theory. We
show that the checkerboard supersolid phase persists at finite temperature
comparable with the interaction energies of bosons.