High frequency, non-gaussian current fluctuations in mesocopic conductors / Fluctuations de courant non-gaussiennes et à haute fréquence dans les conducteurs mésosocopiques

微电子工业的进步使亚微米尺寸的元件的制造成为可能。在这个尺度上，电流所遵循的定律不同于在宏观世界中有效的通常定律。已经进行了许多实验来测量这种结构中的平均电流，特别是在非常低的温度下，其中不寻常的电行为更明显。更微妙但更困难的是电流波动的测量，通常被昵称为“噪音”。电路中噪声的测量才刚刚开始，但它们可能提供有关纳米结构中传导机制的宝贵信息。该计划旨在加强我们对三个方向的电流波动的了解： 1)非高斯噪声的研究。在宏观样品中，噪声来自许多独立的过程，这导致电流波动由高斯定律描述，该定律描述了大多数随机现象。研究噪声的非高斯部分正是研究与通常定律的不同之处。 2)对高频噪音的研究。通过能够测量非常快的电流波动，人们可以获得电子传输的特征时间尺度，例如电子与周围环境交换能量所需的时间。 3)对温度波动的研究。当一个系统足够小时，它的温度不再是很好的定义，它随时间波动。这些波动的测量揭示了纳米结构中的热过程是如何发生的。 除了对知识进步的兴趣之外，这项工作还将为研究新材料提供新的工具，并为微电子工业中的组件特性提供新的方法。

Progress of the industry of micro-electronics have made possible the fabrication of components of submicron size. At that scale, the laws obeyed by the electrical current differ from the usual ones, valid in the macroscopic world. Many experiments have been performed to measure the average current in such structures, in particular at very low temperature, where unusual behavior of electricity is more visible. More subtle, but much more difficult are the measurements of the fluctuations of the current, usually nicknamed "noise". Measurements of noise in circuits are only at their beginning, but they may offer precious information on the conduction mechanisms in nanostructures. This program aims at strengthen our knowledge of current fluctuations in three directions: 1) the study of non-Gaussian noise. In a macroscopic sample, noise results from a number of independent processes, which causes current fluctuations to be described by the Gauss law, the law that describes most of random phenomena. Studying the non-Gaussian part of the noise is precisely looking at what differs from the usual laws. 2) the study of noise at high frequency. By being able to measure very fast current fluctuations, one can gain access to the characteristic time scales of electron transport, such as the time it takes for the electrons to exchange energy with their surroundings. 3) the study of temperature fluctuations. When a system is small enough, its temperature is no longer well defined, it fluctuates in time. The measurement of these fluctuations reveals how thermal processes occur in nanostructures. In addition to its interest for the advance of knowledge, this work will offer new tools to the study of novel materials and new ways to characterize components in the industry of micro-electronics.