Non-Fermi-liquid transport phenomena in bilayer nickelates: Impact of quasi-quantum metric

Abstract: Recently discovered high-$T_c$ superconductivity in thin-film bilayer nickelates La$3$Ni$_2$O$_7$ under ambient pressure has attracted great interest. Non-Fermi-liquid transport behaviors, such as $T$-linear resistivity and positive Hall coefficient increasing at low temperatures, have been reported in this system. In this study, we analyze the non-Fermi-liquid transport phenomena in the thin-film bilayer nickelate La$_3$Ni$_2$O$_7$ using a multiorbital tight-binding model. In La$_3$Ni$_2$O$_7$, the orbital-selective cold spots composed of Ni $d{x^2-y^2}$ orbital emerge since the spin fluctuations cause stronger quasi-particle damping $\gamma$ in the Ni $d_{z^2}$ orbital. Notably, in the present study, we derive a rigorous formula for the Hall coefficient $R_H$ incorporating the $\gamma$ in the quasi-quantum metric (qQM) term. We discover that the $T$-dependence of $\gamma$ in the qQM term is important in determining $R_H$, and that the qQM term is inevitably enhanced by the nearly degenerate bands at the orbital-selective cold spots located around $(\pi/4,\pi/4)$. Moreover, the qQM term plays an essential role in describing the Nernst coefficient and other transport phenomena involving the second derivative velocity $v^{\mu\nu}$. La$_3$Ni$_2$O$_7$ provides a novel platform for exploring the physics of the qQM.