Nonlinear high-frequency hopping conduction in two-dimensional arrays of Ge-in-Si quantum dots: Acoustic methods

Abstract

Using acoustic methods we have measured nonlinear AC conductance in 2D arrays of Ge-in-Si quantum dots. The combination of experimental results and modeling of AC conductance of a dense lattice of localized states leads us to the conclusion that the main mechanism of AC conduction in hopping systems with large localization length is due to the charge transfer within large clusters, while the main mechanism behind its non-Ohmic behavior is charge heating by absorbed power.

Electron-phonon cooling power in Anderson insulators

“…In particular, one can use this approach to analyze the data on bistability of I-V characteristics and switching between high-resistance and low-resistance branches as function of applied voltage, as reported for a number of various semiconductors or insulators, see Refs. [25][26][27][28] . However, one should keep in mind that in insulators with strong Coulomb interaction it might be difficult to disentangle Coulomb correlation effects from purely localization effects.…”

Universal scaling form of AC response in variable range hopping

“…We have simulated the response to an AC electric field as function of frequency for different temperatures in the VRH regime (parts of the numerical data were already presented in Ref. [9]). In most cases we used L = 100, which is sufficient for the DC conductivity to be well defined and sample independent.…”