The voltage-driven breakdown of a Mott insulating state is a phenomenon where both interactions and nonequilibrium effects play crucial roles. This interesting effect has generated significant theoretical and experimental interest, and may also prove technologically relevant. Recent experiments have observed a sharp nonequilibrium insulator-to-metal transition accompanied by hysteresis, negative differential conductance, and lattice deformations, but the underlying breakdown mechanism is highly debated. Here, we describe a minimal lead-driven scenario in which the breakdown can arise from voltage-induced chemical pressure and explore its ramifications for a paradigmatic model of interacting spinless fermions on a chain coupled to metallic reservoirs (leads) and calculate the charge and current responses at the RPA level. We find a complex phase diagram where the nature of the breakdown depends on the strength of the interaction, leading to various current-carrying nonequilibrium phases. For weak to intermediate interaction strengths, we identify a conducting charge-density-wave (CDW) phase with a bias-dependent ordering wave vector. At large interaction strength, the breakdown leads to a charge-separated insulating phase. Additionally, we observe instances of hysteretic behavior, sharp current onset, and negative differential conductance. Our results can help shed light on recent experimental findings and unveil a clean reference mechanism for current-induced breakdown of electronic order.

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• Exotic phases of matter
• 1-dimensional systems
• Mott insulators
• Nonequilibrium systems
• Strongly correlated systems
• Diagrammatic methods
• Non-Markovian processes
• Nonequilibrium Green's function