Superfluid-insulator transitions on the triangular lattice

Kondo metal and ferrimagnetic insulator on the triangular kagome lattice.

We obtain the rich phase diagrams in the Hubbard model on the triangular kagome lattice as a function of interaction, temperature, and asymmetry by combining the cellular dynamical mean-field theory with the continuous time quantum Monte Carlo method. The phase diagrams show the asymmetry separates the critical points in the Mott transition of two sublattices on the triangular kagome lattice an...

Superfluid to Mott Insulator transition in an optical lattice

Structural and insulator-metal quantum phase transitions on a lattice

We consider 2D gas of spinless fermions with the Coulomb and the short range interactions on a square lattice at T = 0. Using exact diagonalization technique we study finite clusters up to 16 particles at filling factors ν = 1/2 and 1/6. By increasing the hopping amplitude we obtain the low-energy spectrum of the system in a wide range from the classical Wigner crystal to almost free gas of fer...

Preroughening and reentrant layering transitions on triangular lattice substrates.

Recent ellipsometric and calorimetric studies of argon and krypton adsorbed on triangular lattice graphite substrates have found a novel sequence of apparent reentrant layering transitions between integer-plus-one-half coverages. Related behavior has been demonstrated in a Monte Carlo study by Phillips, Zhang, and Larese. In contrast to arguments made by these authors, however, we use solidon-s...

Superfluid-insulator transition in a periodically driven optical lattice.

We demonstrate that the transition from a superfluid to a Mott insulator in the Bose-Hubbard model can be induced by an oscillating force through an effective renormalization of the tunneling matrix element. The mechanism involves adiabatic following of Floquet states, and can be tested experimentally with Bose-Einstein condensates in periodically driven optical lattices. Its extension from sma...