Anomalous Thermoelectric Response in an Orbital-Ordered Oxide Near and Far from Equilibrium

Abstract

We report the thermoelectric transport properties in the orbital-ordered Mott insulating phase of Ca${}_2$RuO${}_4$ close to and far from equilibrium. Near equilibrium conditions where the temperature gradient is only applied to the sample, an insulating but non-monotonic temperature variation of the Seebeck coefficient is observed, which is accounted for in terms of a temperature-induced suppression of the orbital order. In non-equilibrium conditions where we have applied high electrical currents, we find that the Seebeck coefficient is anomalously increased in magnitude with increasing external current. The present result clearly demonstrates a non-thermal effect since the heating simply causes a decrease of the Seebeck coefficient, implying a non-trivial non-equilibrium effect such as a modification of the spin and orbital state in currents.

arXiv comment5 pages, 3 figures, Selected as Editors' Choice

References in corpus (12)

• Complexity in Strongly Correlated Electronic Systems
• Nonequilibrium dynamical mean-field theory and its applications
• On the thermoelectricity of correlated electrons in the zero-temperature limit
• Structural and magnetic aspects of the metal insulator transition in Ca${}_{2-x}$Sr${}_x$RuO${}_4$
• Destruction of the Mott Insulating Ground State of Ca_2RuO_4 by a Structural Transition
• Nature of the Mott transition in Ca2RuO4
• Thermoelectric Response Near the Density Driven Mott Transition
• Hallmarks of Hund's coupling in the Mott insulator Ca${}_2$RuO${}_4$
• Prediction of Orbital Ordering in Single-Layered Ruthenates
• Electron and orbital correlations in Ca_{2-x}Sr_{x}RuO_{4} probed by optical spectroscopy
• Current-Induced Gap Suppression in the Mott Insulator Ca${}_2$RuO${}_4$
• Nonequilibrium Peierls Transition

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• Thermoelectric transport properties of the quasi-one-dimensional dimer-Mott insulator ${\beta }^{\prime }$-(BEDT-TTF)${}_2$ICl${}_2$