TY  - JOUR
A1  - Rüger, Robert
A1  - Tocchio, Luca F.
A1  - Valentí, Roser
A1  - Gros, Claudius
T1  - The phase diagram of the square lattice bilayer Hubbard model: a variational Monte Carlo study
T2  - New journal of physics
N2  - We investigate the phase diagram of the square lattice bilayer Hubbard model at half-filling with the variational Monte Carlo method for both the magnetic and the paramagnetic case as a function of the interlayer hopping  and on-site Coulomb repulsion U. With this study we resolve some discrepancies in previous calculations based on the dynamical mean-field theory, and we are able to determine the nature of the phase transitions between metal, Mott insulator and band insulator. In the magnetic case we find only two phases: an antiferromagnetic Mott insulator at small  for any value of U and a band insulator at large . At large U values we approach the Heisenberg limit. The paramagnetic phase diagram shows at small  a metal to Mott insulator transition at moderate U values and a Mott to band insulator transition at larger U values. We also observe a re-entrant Mott insulator to metal transition and metal to band insulator transition for increasing  in the range of . Finally, we discuss the phase diagrams obtained in relation to findings from previous studies based on different many-body approaches.
KW  - Hubbard model
KW  - bilayer square lattice
KW  - band insulator
KW  - Mott insulator
KW  - variational Monte Carlo
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/78743
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-787433
SN  - 1367-2630
VL  - 16
IS  - 033010
PB  - IOP Publishing
CY  - [London]
ER  -