The Frequency Dependent Conductivity of Electron Glasses

Abstract

Results of DC and frequency dependent conductivity in the quantum limit, i.e. hw > kT, for a broad range of dopant concentrations in nominally uncompensated, crystalline phosphorous doped silicon and amorphous niobium-silicon alloys are reported. These materials fall under the general category of disordered insulating systems, which are referred to as electron glasses. Using microwave resonant cavities and quasi-optical millimeter wave spectroscopy we are able to study the frequency dependent response on the insulating side of the metal-insulator transition. We identify a quantum critical regime, a Fermi glass regime and a Coulomb glass regime. Our phenomenological results lead to a phase diagram description, or taxonomy, of the electrodynamic response of electron glass systems.

References in corpus (2)

• Electrodynamics of a Coulomb Glass in n-type Silicon
• Measurements of the Complex Conductivity of NbxSi1-x Alloys on the Insulating Side of the Metal-Insulator Transition

Cited by in corpus (16)

• Electrodynamics of Correlated Electron Materials
• A sudden collapse in the transport lifetime across the topological phase transition in $(B{i}_{1-x}I{n}_x{)}_{2}S{e}_3$
• Antiferromagnetic resonance and terahertz continuum in $\alpha -$RuCl${}_3$
• Terahertz Conductivity at the Verwey Transition in Magnetite
• The Memory Effect in Electron Glasses
• Anomalous 3D bulk AC conduction within the Kondo gap of SmB${}_6$ single crystals
• Signature of Electronic Correlations in the Optical Conductivity of the Doped Semiconductor Si:P
• Conductance relaxation in the Electron-Glass; Microwaves versus infra-red response
• Ultrafast (but Many-Body) Relaxation in a Low-Density Electron Glass
• Influence of electronic correlations on the frequency-dependent hopping transport in Si:P
• Analysis of broadband microwave conductivity and permittivity measurements of semiconducting materials
• Impurities or a neutral Fermi surface? A further examination of the low-energy ac optical conductivity of SmB${}_6$
• Dielectric response of Anderson and pseudogapped insulators
• Two-component Coulomb Glass in Disordered Superconducting Films
• Universal frequency-dependent conduction of electron glasses
• Observation of a marginal Fermi glass using THz 2D coherent spectroscopy