The Mott insulator Ca₂RuO₄ exhibits an insulator-to-metal transition induced by d.c. current. Despite the thorough examination of the structural changes associated with this transition, a comprehensive knowledge of the response of electronic degrees of freedom is still lacking. Here we demonstrate current-induced modifications of the electronic states of Ca₂RuO₄. Angle-resolved photoemission spectroscopy in conjunction with four-probe electrical transport (transport-ARPES) measurements reveal a clear reduction of the Mott gap and a modification in the dispersion of the Ru bands. Based on a free-energy analysis, we show that the current-induced phase is electronically distinct from the high-temperature zero-current metallic phase. Our results highlight strong interplay of lattice- and orbital-dependent electronic responses in the current-driven insulator-to-metal transition.

莫特绝缘体Ca ₂ RuO ₄表现出由直流电流引起的绝缘体到金属的转变。尽管对与这种转变相关的结构变化进行了彻底的检查，但仍然缺乏对电子自由度响应的全面了解。在这里，我们演示了电流引起的 Ca ₂ RuO ₄电子态的改变。角分辨光电子能谱与四探针电传输（传输-ARPES）测量相结合，揭示了莫特带隙的明显减小和Ru带色散的改变。基于自由能分析，我们表明电流感应相在电子上与高温零电流金属相不同。我们的结果强调了电流驱动的绝缘体到金属转变中晶格和轨道相关的电子响应的强烈相互作用。