Transport Properties of Doped t-J Ladders

TL;DR

This paper investigates the transport properties of doped t-J ladders, revealing temperature-dependent crossovers in charge dynamics and pseudogap formation, with implications for understanding correlated electron systems.

Contribution

It provides a detailed numerical analysis of conductivity and Hall effect in t-J ladders, highlighting the effects of dimensionality and pseudogap formation on transport properties.

Findings

Crossover from incoherent to coherent charge dynamics at T_{coh}

Pseudogap opens below T_{PG} due to spin gap formation

Hall coefficient exhibits a significant crossover at T_{PG} with doping dependence

Abstract

Conductivity and Hall coefficient for various types of t-J ladders are calculated as a function of temperature and frequency by numerical diagonalization. A crossover from an incoherent to a coherent charge dynamics is found at a temperature T_{coh}. There exists another crossover at T_{PG} below which a pseudogap opens in the optical spectra, induced by the opening of a spin gap. In the absence of the spin gap, T_{coh} and the coherent weight are suppressed especially with increasing dimensionality. On the contrary, T_{coh} is strongly enhanced by the pseudogap formation below T_{PG}, where the coherent Drude weight decreases with increasing dimensionality. The Hall coefficient shows a strong crossover at T_{PG} below which it has large amplitude for small doping concentration.