Low Temperature Specific Heat of Doped SrTiO${}_3$: Doping Dependence of the Effective Mass and Kadowaki-Woods Scaling Violation

Abstract

We report wide-doping-range ($8\times 10^{17}$ to $4\times 10^{20}$ cm${}^{-3}$ Hall electron density) low temperature specific heat measurements on single crystal SrTiO${}_3$:Nb, correlated with electronic transport data and tight-binding modeling. Lattice dynamic contributions to specific heat are shown to be well understood, albeit with unusual sensitivity to doping, likely related to the behavior of soft modes. Electronic contributions to specific heat provide effective masses that increase substantially, from $1.8$ to $4.8m_e$, across the two SrTiO${}_3$ Lifshitz transitions. It is shown that this behavior can be quantitatively reconciled with quantum oscillation data and calculated band structure, establishing a remarkably doping-independent mass enhancement factor of $2.0$. Most importantly, with the doping-dependent $T^2$ resistivity prefactor and Sommerfeld coefficient known, Kadowaki-Woods scaling has been tested over the entire doping range probed. Despite classic Fermi liquid behavior in electronic specific heat, standard Kadowaki-Woods scaling is dramatically violated, highlighting the need for new theoretical descriptions of $T^2$ resistivity in SrTiO${}_3$.

arXiv commentrevised version accepted for publication as a Rapid Communication in Physical Review Materials; main text + supplementary material

References in corpus (19)

• Unified explanation of the Kadowaki-Woods ratio in strongly correlated materials
• A ferroelectric quantum phase transition inside the superconducting dome of Sr${}_{1-x}$Ca${}_x$TiO${}_{3-\delta }$
• Quantum critical origin of the superconducting dome in SrTiO${}_3$
• Common Fermi-liquid origin of T-squared resistivity and superconductivity in n-type SrTiO3
• Critical doping for the onset of a two-band superconducting ground state in SrTiO${}_{3-\delta }$
• Fermi surface of the most dilute superconductor
• Scalable T^2 resistivity in a small single-component Fermi surface
• Metallicity and superconductivity in doped strontium titanate
• Superconductivity at very low density: the case of strontium titanate
• Persistent Optically Induced Magnetism in Oxygen-Deficient Strontium Titanate
• Origin of the large phonon band-gap in SrTiO3 and the vibrational signatures of ferroelectricity in ATiO3 perovskite: First principles lattice dynamics and inelastic neutron scattering of PbTiO3, BaTiO3 and SrTiO3
• Phonon mechanism in the most dilute superconductor: n-type SrTiO3
• Structure and Correlation Effects in Semiconducting SrTiO${}_3$
• Non-generality of the Kadowaki-Woods ratio in correlated oxides
• Shubnikov-de Haas effect in low electron density SrTiO3: Conduction band edge of SrTiO3 redux
• Metallicity without quasi-particles in room-temperature strontium titanate
• Unconventional multi-band superconductivity in bulk SrTiO${}_3$ and LaAlO${}_3$/SrTiO${}_3$ interfaces
• Carrier density independent scattering rate in SrTiO3-based electron liquids
• Multiple nodeless superconducting gaps in optimally-doped SrTi${}_{1-x}$Nb${}_x$O${}_3$

Cited by in corpus (10)

• Deep Ensembles vs. Committees for Uncertainty Estimation in Neural-Network Force Fields: Comparison and Application to Active Learning
• Quasiparticle and Nonquasiparticle Transport in Doped Quantum Paraelectrics
• On the origin and the amplitude of T-square resistivity in Fermi liquids
• Theory of superconductivity mediated by Rashba coupling in incipient ferroelectrics
• Generalized Rashba Electron-Phonon Coupling and Superconductivity in Strontium Titanate
• T-square dependence of the electronic thermal resistivity in metallic strontium titanate
• Electronic thermal resistivity and quasi-particle collision cross-section in semi-metals
• Soft phonon and the central peak at the cubic-to-tetragonal phase transition in SrTiO${}_3$
• Effects of paramagnetic pair-breaking and spin-orbital coupling on multi-band superconductivity
• Electronic spin susceptibility in metallic strontium titanate