Raman scattering from current-stabilized nonequilibrium phases in Ca${}_2$RuO${}_4$

Abstract

We used Raman light scattering to study the current-stabilized nonequilibrium semimetallic and metallic phases in Ca${}_2$RuO${}_4$. By determining the local temperature through careful analysis of the Stokes and anti-Stokes intensities, we find that Joule heating can be completely avoided by supplying sufficient cooling power in a helium-flow cryostat, and that the current induces the semimetallic state without inducing any significant heating. We further investigate the current-induced semimetallic state as a function of temperature and current. We confirm the absence of long-range antiferromagnetic order and identify a substantial Fano broadening of several phonons, which suggests coupling to charge and orbital fluctuations. Our results demonstrate that the semimetallic state is a genuine effect of the applied electrical current and that the current-induced phases have characteristics distinct from the equilibrium ones.

arXiv commentaccepted for publication as a Rapid Communication in Physical Review B

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Cited by in corpus (10)

• A Unique Crystal Structure of Ca${}_2$RuO${}_4$ in the Current Stabilized Semi-Metallic State
• Picosecond volume expansion drives a later-time insulator-metal transition in a nano-textured Mott Insulator
• Role of local temperature in the current-driven metal-insulator transition of Ca2RuO4
• Current driven insulator-to-metal transition without Mott breakdown in Ca${}_2$RuO${}_4$
• Pseudospin-lattice coupling and electric control of the square-lattice iridate Sr2IrO4
• Sr${}_2$RuO${}_4$, like doped cuprates and barium bismuthate, is a negative charge-transfer gap even parity superconductor with $\frac{3}{4}$-filled oxygen band
• Nature of the current-induced insulator-to-metal transition in Ca${}_2$RuO${}_4$ as revealed by transport-ARPES
• Diamagnetic-like response from localised heating of a paramagnetic material
• Challenges in extracting nonlinear current-induced phenomena in Ca2RuO4
• Universal size-dependent nonlinear charge transport in single crystals of the Mott insulator Ca${}_2$RuO${}_4$