Experimental Studies of Quantum Dynamics of Electrons in Disordered Metals

9423088卡里尼这个项目研究电子接近局域化转变的无序金属的微波导电性(频率高达20兆赫)，例如超薄金属薄膜和高度无序的金属合金。实验将比较直流和微波电导率作为温度(T30mK)和磁场(B8T)的函数。这些测量将检验标度理论的预测，该理论将转变视为一个量子临界点，其中温度、合金浓度和电导率的频率依赖于相同的临界长度尺度。所提出的实验研究了当电子在空间中局域化时，无序材料中发生的从金属态到绝缘态的转变。局域化转变是由于电子作为量子力学粒子的波动行为而发生的，但这种转变是系统所有部分同时经历相同状态变化的集体现象。这些实验将测量无序金属的电导率，以了解量子力学如何影响导电态和绝缘态之间的转变。***

9423088 Carini This project investigates the microwave conductivity (up to a frequency of 20 megahertz) of disordered metals in which the electrons are close to a localization transition, such as ultrathin metal films and highly disordered metal alloys. Experiments will compare the dc and microwave conductivity as a function of temperature (T30mK) and magnetic field (B8T). Theses measurements will test the predictions of the scaling theory, which treats the transition as a quantum-critical point where the temperature, alloy concentration, and frequency dependence of the conductivity are related to the same critical length-scale. % % % The proposed experiments study the transition from the metallic state to the insulating state that occurs in disordered materials when the electrons become localized in space. The localization transition occurs because of the wavelike behavior of the electrons as quantum mechanical particles, and yet the transition is a collective phenomenon where all parts of the system undergo the same change of state at the same time. The experiments will measure the electrical conductivity in disordered metals in order to understand how quantum mechanics affects the transition between the conducting and insulating states. ***