Sufficiently large electric current applied to metallic nanostructures can bring them far out of equilibrium, resulting in non-Ohmic behaviors characterized by current-dependent resistance. We experimentally demonstrate a linear dependence of resistance on current in microscopic thin-film metallic wires at cryogenic temperatures, and show that our results are inconsistent with common non-Ohmic mechanisms such as Joule heating. As the temperature is increased, the linear dependence becomes smoothed out, resulting in the crossover to behaviors consistent with Joule heating. A plausible explanation for the observed behaviors is the strongly nonequilibrium distribution of phonons generated by the current. Analysis based on this interpretation suggests that the observed anomalous current-dependent resistance can provide information about phonon transport and electron-phonon interaction at nanoscale. The ability to control the properties of phonons generated by current can lead to new routes for the optimization of thermal properties of electronic nanodevices.

中文翻译：

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电流驱动纳米结构中异常非欧姆传输的观察

施加到金属纳米结构的足够大的电流会使它们远远失去平衡，导致以电流相关电阻为特征的非欧姆行为。我们通过实验证明了低温条件下微观薄膜金属线中电阻对电流的线性依赖性，并表明我们的结果与常见的非欧姆机制（如焦耳加热）不一致。随着温度升高，线性相关性变得平滑，从而导致行为转变为与焦耳加热相一致的行为。对于观察到的行为的合理解释是电流产生的声子的强烈非平衡分布。基于这种解释的分析表明，观察到的异常电流依赖性电阻可以提供有关纳米级声子传输和电子-声子相互作用的信息。控制电流产生的声子的性能的能力可以导致优化电子纳米器件的热性能的新途径。