Band-Insulator-Metal-Mott-Insulator transition in the half--filled $t-t^{\prime }$ ionic-Hubbard chain

Abstract

We investigate the ground state phase diagram of the half-filled $t-t^{\prime }$ repulsive Hubbard model in the presence of a staggered ionic potential $\Delta$, using the continuum-limit bosonization approach. We find, that with increasing on-site-repulsion $U$, depending on the value of the next-nearest-hopping amplitude $t^{\prime }$, the model shows three different versions of the ground state phase diagram. For $t^{\prime }<t_{\ast }^{\prime }$, the ground state phase diagram consists of the following three insulating phases: Band-Insulator at $U<U_c$, Ferroelectric Insulator at $U_c<U<U_s$ and correlated (Mott) Insulator at $U>U_c$. For $t^{\prime }>t_c^{\prime }$ there is only one transition from a spin gapped metallic phase at $U<U_c$ to a ferroelectric insulator at $U>U_c$. Finally, for intermediate values of the next-nearest-hopping amplitude $t_{\ast }^{\prime }<t^{\prime }<t_c^{\prime }$ we find that with increasing on-site repulsion, at $U_{c1}$ the model undergoes a second-order commensurate-incommensurate type transition from a band insulator into a metallic state and at larger $U_{c2}$ there is a Kosterlitz-Thouless type transition from a metal into a ferroelectric insulator.

9 pages 3 figures

References in corpus (1)

• Breakdown of the Luttinger sum-rule at the Mott-Hubbard transition in the one-dimensional t1-t2 Hubbard model

Cited by in corpus (1)

• Electronic phase transitions in the half-filled ionic Hubbard model