Current-Induced Gap Suppression in the Mott Insulator Ca${}_2$RuO${}_4$

Abstract

We present nonlinear conduction phenomena in the Mott insulator Ca2RuO4 investigated with a proper evaluation of self-heating effects. By utilizing a non-contact infrared thermometer, the sample temperature was accurately determined even in the presence of large Joule heating. We find that the resistivity continuously decreases with currents under an isothermal environment. The nonlinearity and the resulting negative differential resistance occurs at relatively low current range, incompatible with conventional mechanisms such as hot electron or impact ionization. We propose a possible current-induced gap suppression scenario, which is also discussed in non-equilibrium superconducting state or charge-ordered insulator.

5 pages, 3 figures, to be published in J. Phys. Soc. Jpn

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Cited by in corpus (34)

• High-order Harmonic Generation and its Unconventional Scaling Law in the Mott-insulating $\mathrm{C}{\mathrm{a}}_2\mathrm{Ru}{\mathrm{O}}_4$
• Observation of spin-orbit excitations and Hund's multiplets in Ca${}_2$RuO${}_4$
• Current-induced giant diamagnetism in the Mott insulator Ca2RuO4
• A Unique Crystal Structure of Ca${}_2$RuO${}_4$ in the Current Stabilized Semi-Metallic State
• Nonequilibrium Orbital Transitions via Applied Electrical Current in Calcium Ruthenate
• Emergence of a metallic meta-stable phase induced by electrical current in Ca_2RuO_4
• Raman scattering from current-stabilized nonequilibrium phases in Ca${}_2$RuO${}_4$
• Polarity dependent heating at the phase interface in metal-insulator transitions
• Role of local temperature in the current-driven metal-insulator transition of Ca2RuO4
• Evidence for current-induced phase coexistence in Ca${}_2$RuO${}_4$ and its influence on magnetic order
• Voltage induced metal-insulator transition in a one dimensional charge density wave
• Anomalous Thermoelectric Response in an Orbital-Ordered Oxide Near and Far from Equilibrium
• Current driven insulator-to-metal transition without Mott breakdown in Ca${}_2$RuO${}_4$
• Separated transport relaxation scales and interband scattering in SrRuO${}_3$, CaRuO${}_3$, and Sr${}_2$RuO${}_4$ thin films
• Pattern Formation by Electric-field Quench in Mott Crystal
• 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
• Towards Electrical-Current Control of Quantum States in Spin-Orbit-Coupled Matter
• Magnetic reorientation transition in a three orbital model for $\mathrm{C}{\mathrm{a}}_2\mathrm{Ru}{\mathrm{O}}_4$ -- Interplay of spin-orbit coupling, tetragonal distortion, and Coulomb interactions
• Diamagnetic-like response from localised heating of a paramagnetic material
• In situ control of diamagnetism by electric current in Ca${}_3$(Ru${}_{1-x}$Ti${}_x$)${}_2$O${}_7$
• Nature of the current-induced insulator-to-metal transition in Ca${}_2$RuO${}_4$ as revealed by transport-ARPES
• Correlation-driven organic 3D topological insulator with relativistic fermions
• Spin-orbit coupling and crystal-field splitting in Ti-doped Ca2RuO4 studied by ellipsometry
• Nonlinear transport associated with spin-density-wave dynamics in Ca${}_3$Co${}_4$O${}_9$
• Mott-Insulator Ca2RuO4 under a static external electric field
• Emerging new phases in correlated Mott insulator Ca2RuO4
• Challenges in extracting nonlinear current-induced phenomena in Ca2RuO4
• Role of orbital off-diagonal spin and charge condensates in a three orbital model for $\mathrm{C}{\mathrm{a}}_2\mathrm{Ru}{\mathrm{O}}_4$ -- Coulomb renormalized spin-orbit coupling, orbital moment, and tunable magnetic order
• Coupled spin-orbital fluctuations in a three orbital model for $4d$ and $5d$ oxides with electron fillings $n=3,4,5$ -- Application to $\mathrm{NaOs}{\mathrm{O}}_3$, $\mathrm{C}{\mathrm{a}}_2\mathrm{Ru}{\mathrm{O}}_4$, and $\mathrm{S}{\mathrm{r}}_2\mathrm{Ir}{\mathrm{O}}_4$
• Metallisation of the Mott Insulator Ca${}_2$RuO${}_4$ using Electric Double-Layer Gating
• Third-order Electrical Conductivity of the Charge-ordered Organic Salt $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Universal size-dependent nonlinear charge transport in single crystals of the Mott insulator Ca${}_2$RuO${}_4$
• Current-induced successive structural phase transitions beyond thermal equilibrium in single-crystal VO2