2002/10/21 by E. Helgren, N. P. Armitage, G. Grüner +1 · 2 citations
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Quantum and electron transport phenomena #Semiconductor materials and devices #cond-mat.dis-nn #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.89.246601
5 pages, 4 figures; accepted for publication in Phys. Rev. Lett
arxiv created 2002/10/21 · openalex publication_date 2002/11/25 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Measurements of the complex frequency dependent conductivity of uncompensated n-type silicon are reported. The experiments are done in the quantum limit, variant Planck's over 2pi omega>k(B)T, across a broad doping range on the insulating side of the metal-insulator transition. The low energy linear frequency dependence is consistent with theories of a Coulomb glass, but discrepancies exist in the relative magnitudes of the complex components. At higher energies we observe a crossover to a quadratic frequency dependence that is sharper than expected. The concentration dependence gives evidence that the Coulomb interaction energy is the energy scale that determines this crossover.