Orbital-cooperative spin fluctuation and orbital-dependent transport in ruthenates

Abstract

Unusual transport properties deviating from the Fermi liquid are observed in ruthenates near a magnetic quantum-critical point (QCP). To understand the electronic properties of the ruthenates near and away from an antiferromagnetic (AF) QCP, I study the electronic structure and magnetic and transport properties for the $t_{2g}$-orbital Hubbard model on a square lattice in fluctuation-exchange approximation including Maki-Thompson (MT) current vertex correction (CVC). The results away from the AF QCP reproduce several experimental results of Sr${}_2$RuO${}_4$ qualitatively and provide new mechanisms about the enhancement of spin fluctuation at $Q_{\text{IC-AF}}\approx (0.66\pi ,0.66\pi )$, larger mass enhancement of the $d_{xy}$ orbital than that of the $d_{xz/yz}$ orbital, and nonmonotonic temperature dependence of the Hall coefficient. Also, the results near the AF QCP explain the $T$-linear inplane resistivity in Sr${}_2$Ru${}_{0.075}$Ti${}_{0.025}$O${}_4$ and give an experimental test on the obtained temperature dependence of the Hall coefficient. I reveal spatial correlation including the self-energy of electrons beyond mean-field approximations is essential to determine the electronic properties of the ruthenates. I also show several ubiquitous transport properties near an AF QCP and characteristic transport properties of a multiorbital system by comparison with results of a single-orbital system near an AF QCP.

6 pages, 3 figures

References in corpus (2)

• The coherence-incoherence crossover and the mass-renormalization puzzles in Sr2RuO4
• Fourth-Order Perturbation Expansion for Hubbard Model on a Two-Dimensional Square Lattice

Cited by in corpus (5)

• Spin-triplet superconductivity in Sr2RuO4 due to orbital and spin fluctuations: Analyses by two-dimensional renormalization group theory and self-consistent vertex-correction method
• Spin Triplet Superconductivity in Sr2RuO4 due to Orbital and Spin Fluctuations: Analysis by Two-Dimensional Renormalization Group Theory
• Symmetry-protected difference between spin Hall and anomalous Hall effects of a periodically driven multiorbital metal
• Many-body effects on the resistivity of a multiorbital system beyond Landau's Fermi-liquid theory
• Onsager Reciprocal Relations for Charge and Spin Transport in Periodically Driven Systems