  Recently, application of electric field (E-field) has received considerable
attention as a new method to induce novel quantum phenomena since application
of E-field can tune the electronic states directly with obvious scientific and
industrial advantages over other turning methods. However, E-field-induced Mott
transitions are rare and typically require high E-field and low temperature.
Here we report that the multiband Mott insulator Ca2RuO4 shows unique
insulator-metal switching induced by applying a dry-battery level voltage at
room temperature. The threshold field Eth ~40 V/cm is much weaker than the Mott
gap energy. Moreover, the switching is accompanied by a bulk structural
transition. Perhaps the most peculiar of the present findings is that the
induced metal can be maintained to low temperature by a weak current.
