Microscopic theory on charge transports of a correlated multiorbital system

Abstract

Current vertex correction (CVC), the back-flow-like correction to the current, comes from conservation laws, and the CVC due to electron correlation contains information about many-body effects. However, it has been little understood how the CVC due to electron correlation affects the charge transports of a correlated multiorbital system. To improve this situation, I studied the inplane resistivity, ${\rho }_{ab}$, and the Hall coefficient in the weak-field limit, $R_{\text{H}}$, in addition to the magnetic properties and the electronic structure, for a $t_{2g}$-orbital Hubbard model on a square lattice in a paramagnetic state away from or near an antiferromagnetic (AF) quantum-critical point (QCP) in the fluctuation-exchange (FLEX) approximation with the CVCs arising from the self-energy ($\Sigma$), the Maki-Thompson (MT) irreducible four-point vertex function, and the main terms of the Aslamasov-Larkin (AL) one. Then, I found three main results about the CVCs. First, the main terms of the AL CVC does not qualitatively change the results obtained in the FLEX approximation with the $\Sigma$ CVC and the MT CVC. Second, ${\rho }_{ab}$ and $R_{\text{H}}$ near the AF QCP have high-temperature region, governed mainly by the $\Sigma$ CVC, and low-temperature region, governed mainly by the $\Sigma$ CVC and the MT CVC. Third, in case away from the AF QCP, the MT CVC leads to a considerable effect on only $R_{\text{H}}$ at low temperatures, although $R_{\text{H}}$ at high temperatures and ${\rho }_{ab}$ at all temperatures considered are sufficiently described by including only the $\Sigma$ CVC. I also achieved the qualitative agreement with several experiments of Sr${}_2$RuO${}_4$ or Sr${}_2$Ru${}_{0.975}$Ti${}_{0.025}$O${}_4$. Moreover, I showed several better points of this theory than other theories.

43 pages, 23 figures, 1 table; published version

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Cited by in corpus (5)

• Hall and Faraday effects in interacting multi-band systems with arbitrary band topology and spin-orbit coupling
• Weak localization of magnons in a disordered two-dimensional antiferromagnet
• Inplane anisotropy of longitudinal thermal conductivities and weak localization of magnons in a disordered spiral magnet
• Interband magnon drag in ferrimagnetic insulators
• Negative magneto-thermal-resistance in a disordered two-dimensional antiferromagnet