Low-temperature transport in high-conductivity correlated metals: a density-functional plus dynamical mean-field study of cubic perovskites

Abstract

While methods based on density-functional perturbation theory have dramatically improved our understanding of electron-phonon contributions to transport in materials, methods for accurately capturing electron-electron scattering relevant to low temperatures have seen significantly less development. The case of high-conductivity, moderately correlated materials characterized by low scattering rates is particularly challenging, since exquisite numerical precision of the low-energy electronic structure is required. Recent methodological advancements to density-functional theory combined with dynamical mean-field theory (DFT+DMFT), including adaptive Brillouin-zone integration and numerically precise self-energies, enable a rigorous investigation of electron-electron scattering in such materials. In particular, these tools may be leveraged to perform a robust scattering-rate analysis on both real- and imaginary-frequency axes. Applying this methodology to a subset of ABO$_3$ perovskite oxides -- SrVO$_3$, SrMoO$_3$, PbMoO$_3$, and SrRuO$_3$ -- we demonstrate its ability to qualitatively and quantitatively describe electron-electron contributions to the temperature-dependent direct-current resistivity. This combination of numerical techniques offers fundamental insight into the role of electronic correlations in transport phenomena and provides a predictive tool for identifying materials with potential for technological applications.

Figures (11)

• Figure 1: (a) Crystal structure for cubic ($Pm\overline{3}m$) ABO$_{3}$ perovskites, where A, B, and O are denoted as green, blue, and red spheres, respectively. (b) DFT band structures (black lines) compared with Wannier dispersion (light blue) along high-symmetry lines in the Brillouin zone for cubic ($Pm\overline{3}m$) SrVO$_3$, SrMoO$_3$, PbMoO$_3$, and SrRuO$_3$. Shaded region (light purple) denotes the frozen window used for the downfolding scheme as implemented in Wannier90.
• Figure 2: Convergence of SrMoO$_3$ DFT calculated properties at the Fermi level $\epsilon_{\mathrm{F}}$. (a) DOS and transport function for various broadening $\eta$, obtained with the iterated adaptive integrator (IAI). Relative differences are taken from the values $V_{\mathrm{uc}}D(\epsilon_{\mathrm{F}}) = 1.886$/eV, $\Phi(\epsilon_{\mathrm{F}}) = 3.930\,$eV/($\Omega\,$cm). (b) DOS (solid lines) and transport function (dotted lines) at each value of $\eta$ computed with a fixed number of $k$ points, $N_k$, per dimension in the full BZ. Differences are taken from the IAI result at the respective value of $\eta$.
• Figure 3: (a) Density of the $t_{2g}$ states and (b) transport function of all four materials using IAI with $\eta=1$ meV.
• Figure 4: QMC (blue) and NRG (orange) comparison of the DMFT self-energy on the Matsubara imaginary-frequency axis (top) and the real-frequency axis (bottom) for SrVO$_3$, SrMoO$_3$, PbMoO$_3$, and SrRuO$_3$ at $T = 116$ K ($\beta = 100$/eV). The dashed (black) lines indicate a fit of the real-frequency data to the Fermi-liquid form $C(\omega^2 + \pi^2 T^2)$. The Fermi-liquid fit to SrRuO$_3$ is clearly not successful. We note that increasing $C$ to match $\mathrm{Im}\,\Sigma(0)$ does not lead to an overall better fit.
• Figure 5: QMC results for the imaginary part of the self-energy at the first Matsubara frequency as a function of $T$. Fermi-liquid behavior indicated by $\mathrm{Im}\Sigma(i\pi T)/T = \mathrm{const}$Chubukov2012 is seen below a crossover scale of $T \sim 500\,$K for SrVO$_3$, SrMoO$_3$, PbMoO$_3$, but does not occur above $T_0 \approx 116\,$K for SrRuO$_3$.