Charge and spin gaps of the ionic Hubbard model with density-dependent hopping
We calculate the charge gap $ΔE_C$ and the spin gap $ΔE_S$ of the ionic Hubbard chain including electron-hole symmetric density-dependent hopping. The vanishing of $ΔE_C$ ($ΔE_S$) signals a quantum critical point (QCP) in the charge (spin) sector. Between both critical points, the system is a fully gapped spontaneously dimerized insulator (SDI). We focus our study in this region. Including alternation in the hopping, it is possible to perform an adiabatic Thouless pump of one charge per cycle, but with a velocity limited by the size of the gaps.
cond-mat.str-el↗