Phase diagram for the exciton Mott transition in infinite-dimensional electron-hole systems

Abstract

To understand the essence of the exciton Mott transition in three-dimensional electron-hole systems, the metal-insulator transition is studied for a two-band Hubbard model in infinite dimensions with interactions of electron-electron (hole-hole) repulsion U and electron-hole attraction -U'. By using the dynamical mean-field theory, the phase diagram in the U-U' plane is obtained (which is exact in infinite dimensions) assuming that electron-hole pairs do not condense. When both electron and hole bands are half-filled, two types of insulating states appear: the Mott-Hubbard insulator for U > U' and the biexciton-like insulator for U < U'. Even when away from half-filling, we find the phase transition between the exciton- or biexciton-like insulator and a metallic state. This transition can be assigned to the exciton Mott transition, whereas the Mott-Hubbard transition is absent.

arXiv comment4 pages, 4 figures, submitted to EXCON '04

References in corpus (4)

• Orbital-selective Mott transitions in the degenerate Hubbard model
• Two-site dynamical mean-field theory
• First-Order Pairing Transition and Single-Particle Spectral Function in the Attractive Hubbard Model
• Stability of a metallic state in the two-orbital Hubbard model

Cited by in corpus (5)

• Spin, charge and orbital fluctuations in a multi-orbital Mott insulator
• Metal-insulator transition in the two-orbital Hubbard model at fractional band fillings: Self-energy functional approach
• Excitonic BCS-BEC crossover at finite temperature: Effects of repulsion and electron-hole mass difference
• Phase diagram of orbital-selective Mott transitions at finite temperatures
• Excitonic condensation reflecting electronic states in two-band Penrose-Hubbard model