Temperature-frequency scaling in amorphous niobium-silicon near the metal-insulator transition

Hok-Ling Lee; John P. Carini; David V. Baxter; George Gruner

doi:10.1103/physrevlett.80.4261

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Temperature-frequency scaling in amorphous niobium-silicon near the metal-insulator transition

Hok-Ling Lee·John P. Carini·David V. Baxter·George Gruner

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Abstract

Millimeter-wave transmission measurements have been performed in amorphous niobium-silicon alloy samples where the DC conductivity follows the critical temperature dependence $σ_{dc} \propto T^{1/2}$. The real part of the conductivity is obtained at eight frequencies in the range 87--1040 GHz for temperatures 2.6 K and above. In the quantum regime ($\hbar ω> k_B T$) the real part of the high-frequency conductivity has a power-law frequency dependence $Re~σ(ω) \propto ω^{1/2}$. For temperatures 16 K and below the data exhibits temperature-frequency scaling predicted by theories of dynamics near quantum-critical points.

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Hok-Ling Lee, John P. Carini, David V. Baxter, George Gruner. 1998-03-24. Temperature-frequency scaling in amorphous niobium-silicon near the metal-insulator transition. https://doi.org/10.1103/physrevlett.80.4261

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