Lee H, Carini JP, Baxter DV, Henderson W, Gruner G
Department of Physics, Indiana University, Bloomington, IN 47405, USA. Department of Physics, University of California, Los Angeles, CA 90095-1547, USA.
Science. 2000 Jan 28;287(5453):633-6. doi: 10.1126/science.287.5453.633.
Temperature (T)- and frequency (omega)-dependent conductivity measurements are reported here in amorphous niobium-silicon alloys with compositions (x) near the zero-temperature metal-insulator transition. There is a one-to-one correspondence between the frequency- and temperature-dependent conductivity on both sides of the critical concentration, thus establishing the quantum-critical nature of the transition. The analysis of the conductivity leads to a universal scaling function and establishes the critical exponents. This scaling can be described by an x-, T-, and omega-dependent characteristic length, the form of which is derived by experiment.
本文报道了在零温度金属-绝缘体转变附近成分（x）的非晶铌硅合金中，温度（T）和频率（ω）相关的电导率测量结果。在临界浓度两侧，频率和温度相关的电导率之间存在一一对应关系，从而确立了转变的量子临界性质。对电导率的分析得出了一个通用的标度函数，并确定了临界指数。这种标度可以用一个与x、T和ω相关的特征长度来描述，其形式由实验得出。
