Low-Temperature Transport and Spectroscopy — Dynamical Mean-Field Theory Meets Experiment

Quantum materials research has advanced significantly in recent years. On the theory side, much progress has been made with quantum embedding techniques. Nevertheless, there are still many challenges: Connecting theory to experiment requires simulations at low temperatures, which is numerically costly for many algorithms. Moreover, computing transport and spectroscopic properties requires fine real-frequency resolution, which is notoriously difficult. Here, we show how these challenges can be addressed in the framework of density functional theory and dynamical mean-field theory (DMFT). We present results obtained with various DMFT impurity solvers, highlight advances made with the numerical renormalization group, and discuss recent applications to paradigmatic systems.

First, we consider the Fermi-liquid regime of transport in two moderately correlated perovskite oxides, SrVO₃ and SrMoO₃. From our simulations, we carefully extract the electron-electron scattering rate and compute the direct-current resistivity. Remarkably, we find agreement with low-temperature resistivity measurements performed on samples with exceptionally low residual resistivity [1]. Second, we consider LiV₂O₄, a so-called heavy-fermion transition-metal oxide. We show that the remarkably small Fermi-liquid coherence scale and large effective mass observed are due to the proximity of a Hund-assisted orbital-selective Mott state. We further reveal how a flat quasiparticle band appears near the Fermi level because of the strong electronic correlations [2].

[1] J. Lee-Hand, H. LaBollita, F. B. Kugler, L. Van Muñoz, S. Beck, A. Hampel, J. Kaye, A. Georges, C. E. Dreyer, in preparation

[2] M. Grundner, F. B. Kugler, O. Parcollet, U. Schollwöck, A. Georges, A. Hampel, arXiv:2409.17268