直流电场下非平衡绝缘体中戈德斯通模式的作用
Role of Goldstone mode in nonequilibrium insulator under DC electric field
AI总结：
该研究针对直流电场下绝缘体-金属转变阈值场低于单电子激发理论预测的问题，提出戈德斯通模式激发的失稳机制，经Keldysh格林函数数值验证，发现其可降低转变场至实验范围。
AI中文摘要：
对直流电场下电子系统的电阻击穿测量表明，绝缘体到金属转变的阈值场显著低于单电子激发场景（如朗道-齐纳理论）的预测值。本工作提出了一种替代机制：通过戈德斯通模式激发引起的序参量涨落，使直流电场下的有序绝缘体失稳。低能玻色型激发从加速电子处获取能量，从而破坏自发对称性破缺。我们采用Keldysh格林函数形式主义进行数值计算，证实戈德斯通模式在非平衡稳态下仍保持明确性，但其非平衡激发对电场敏感；戈德斯通模式的有效温度增长速率远快于电子有效温度，且玻色型阈值场显著小于电子阈值场，这表明集体相动力学可通过纯电子机制进一步将转变场降低至实验范围内。
英文摘要：
Measurements of resistive breakdown in electronic systems under a DC electric field have shown that the threshold fields for the insulator-to-metal transition are significantly lower than predicted by single-electron excitation scenarios, such as the Landau-Zener theory. In this work, we propose an alternate mechanism of destabilizing ordered insulators under a DC electric field by fluctuations of the order parameters through the Goldstone mode excitation. The low-energy bosonic excitations receive energy from accelerated electrons and thus destroy the spontaneous symmetry breaking. Using the Keldysh Gree's function formalism, we numerically confirm that the Goldstone mode remains well-defined in the nonequilibrium steady state, while its nonequilibrium excitations are sensitive to the electric field. The effective temperature of the Goldstone mode increases much more rapidly than the electronic effective temperature, with the bosonic threshold field significantly smaller than the electronic one, which suggests that collective phase dynamics may further reduce the transition field to the experimental range via a purely electronic mechanism.
