Universal size-dependent nonlinear charge transport in single crystals of the Mott insulator Ca${}_2$RuO${}_4$

Abstract

The surprisingly low current density required for inducing the insulator to metal transition has made Ca${}_2$RuO${}_4$ an attractive candidate material for developing Mott-based electronics devices. The mechanism driving the resistive switching, however, remains a controversial topic in the field of strongly correlated electron systems. Here we probe an uncovered region of phase space by studying high-purity Ca${}_2$RuO${}_4$ single crystals, using the sample size as principal tuning parameter. Upon reducing the crystal size, we find a four orders of magnitude increase in the current density required for driving Ca${}_2$RuO${}_4$ out of the insulating state into a non-equilibrium (also called metastable) phase which is the precursor to the fully metallic phase. By integrating a microscopic platinum thermometer and performing thermal simulations, we gain insight into the local temperature during simultaneous application of current and establish that the size dependence is not a result of Joule heating. The findings suggest an inhomogeneous current distribution in the nominally homogeneous crystal. Our study calls for a reexamination of the interplay between sample size, charge current, and temperature in driving Ca${}_2$RuO${}_4$ towards the Mott insulator to metal transition.

References in corpus (26)

• The Large N Limit of Superconformal Field Theories and Supergravity
• Evidence for hydrodynamic electron flow in PdCoO${}_2$
• Evaluation of Spin-Triplet Superconductivity in Sr2RuO4
• Strong Peak in $T_c$ of Sr${}_2$RuO${}_4$ Under Uniaxial Pressure
• Visualizing Poiseuille flow of hydrodynamic electrons
• Holographic quantum matter
• 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
• Split superconducting and time-reversal symmetry-breaking transitions, and magnetic order in Sr${}_2$RuO${}_4$ under uniaxial stress
• Nature of the Mott transition in Ca2RuO4
• From Mott insulator to ferromagnetic metal: a pressure study of Ca${}_2$RuO${}_4$
• Resistivity in the Vicinity of a Van Hove Singularity: Sr${}_2$RuO${}_4$ Under Uniaxial Pressure
• Orbital ordering transition in Ca${}_2$RuO${}_4$ observed with resonant x-ray diffraction
• High pressure diffraction studies on Ca2RuO4
• Current-Induced Gap Suppression in the Mott Insulator Ca${}_2$RuO${}_4$
• A Unique Crystal Structure of Ca${}_2$RuO${}_4$ in the Current Stabilized Semi-Metallic State
• Colossal magnetoresistance in a Mott insulator via magnetic field-driven insulator-metal transition
• Tailoring the electronic properties of Ca${}_2$RuO${}_4$ via epitaxial strain
• Emergence of a metallic meta-stable phase induced by electrical current in Ca_2RuO_4
• Orbitally selective breakdown of Fermi liquid quasiparticles in Ca${}_{1.8}$Sr${}_{0.2}$RuO${}_4$
• Spontaneous emergence of Josephson junctions in homogeneous rings of single-crystal Sr2RuO4
• 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
• Optical imaging of strain-mediated phase coexistence during electrothermal switching in a Mott insulator