Quantum criticality associated with dimensional crossover in the iso-electronic series Ca2−x Sr x RuO4

Acharya, Swagata; Dey, Dibyendu; Maitra, T.; Taraphder, A.

doi:10.1088/2399-6528/aace29

Cited by 7 publications

(7 citation statements)

References 68 publications

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“…As a first step, comparison to the band structure calculations is made. Although details can vary depending on exact methodology, all band structure calculations of Ca 2 RuO 4 find a single fast dispersing branch 22 23 24 25 . Our DFT calculation reveals that the fast dispersing band has predominantly d xy character ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

Sutter

Fatuzzo

Moser³

et al. 2017

Nat Commun

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A paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling is realized in Ca2RuO4. Progress in understanding the nature of this Mott insulating phase has been impeded by the lack of knowledge about the low-energy electronic structure. Here we provide—using angle-resolved photoemission electron spectroscopy—the band structure of the paramagnetic insulating phase of Ca2RuO4 and show how it features several distinct energy scales. Comparison to a simple analysis of atomic multiplets provides a quantitative estimate of the Hund's coupling J=0.4 eV. Furthermore, the experimental spectra are in good agreement with electronic structure calculations performed with Dynamical Mean-Field Theory. The crystal field stabilization of the dxy orbital due to c-axis contraction is shown to be essential to explain the insulating phase. These results underscore the importance of multi-band physics, Coulomb interaction and Hund's coupling that together generate the Mott insulating state of Ca2RuO4.

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Section: Resultsmentioning

confidence: 99%

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

Sutter

Fatuzzo

Moser³

et al. 2017

Nat Commun

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“…In particular, the multi-orbital nature of the spin and charge fluctuations and many-body correlations are shown to be important in SRO (15,16,17,18). Novel electron correlations originating from competition between non-local Coulomb repulsion and the large Hund's coupling (19,15,20) are also significant.…”

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confidence: 99%

Evening out the spin and charge parity to increase T$_c$ in unconventional superconductor Sr_{2}RuO_{4}

Acharya,

Pashov,

Weber

et al. 2018

Preprint

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Unconventional superconductivity in Sr 2 RuO 4 has been intensively studied for decades. The origin and nature of the pairing continues to be widely debated, in particular, the possibility of a triplet origin of Cooper pairs. However, complexity of Sr 2 RuO 4 with multiple low-energy scales, involving subtle interplay among spin, charge and orbital degrees of freedom, calls for advanced theoretical approaches which treat on equal footing all electronic effects. Here we develop a novel approach, a detailed ab initio theory, coupling quasiparticle self-consistent GW approximation with dynamical mean field theory (DMFT), including both local and non-local correlations. We report that the superconducting instability has multiple triplet and singlet components. In the unstrained case the triplet eigenvalues are larger than the singlets. Under uniaxial strain, the triplet eigenvalues drop rapidly and the singlet components increase. This is concomitant with our observation of spin and charge fluctu-1

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“…In particular, the multi-orbital nature of the spin and charge fluctuations and many-body correlations are shown to be important in SRO [14][15][16][17] . Novel electron correlations originating from competition between non-local Coulomb repulsion and the large Hund's coupling 14,18,19 are also significant.…”

mentioning

confidence: 99%

Evening out the spin and charge parity to increase $${T}_{c}$$ in $${{\rm{Sr}}}_{2}{{\rm{RuO}}}_{4}$$

et al. 2019

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Unconventional superconductivity in Sr 2 RuO 4 has been intensively studied for decades. However, the nature of pairing continues to be widely debated. Here we develop a detailed ab initio theory, coupling quasiparticle self-consistent GW approximation with dynamical mean field theory (DMFT), including both local and non-local correlations to address the subtle interplay among spin, charge and orbital degrees of freedom. We report that the superconducting instability has multiple triplet and singlet components. In the unstrained case the triplet eigenvalues are larger than the singlets. Under uniaxial strain, the triplet eigenvalues drop and the singlet components increase. This is concomitant with our observation of spin and charge fluctuations shifting closer to wave-vectors favoring singlet pairing. We identify a complex mechanism where charge fluctuations and spin fluctuations cooperate in the evenparity channel under strain leading to increment in critical temperature (Tc), thus proposing a novel mechanism for pushing the frontier of critical temperature (Tc) in unconventional 'triplet' superconductors.

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Quantum criticality associated with dimensional crossover in the iso-electronic series Ca_2−xSr_xRuO₄

Cited by 7 publications

References 68 publications

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

Evening out the spin and charge parity to increase T$_c$ in unconventional superconductor Sr_{2}RuO_{4}

Evening out the spin and charge parity to increase $${T}_{c}$$ in $${{\rm{Sr}}}_{2}{{\rm{RuO}}}_{4}$$

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