Coulomb gap revisited – a renormalisation approach

Möbius, A.; Karmann, Peter; Schreiber, Michael

doi:10.1088/1742-6596/150/2/022057

Cited by 7 publications

(6 citation statements)

References 5 publications

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“…The co-efficient α is basically independent of the type of lattice, the filling fraction, and the details of the disorder 33,34 . We find a value α ≈ 0.35 ± 0.01 consistent with previous numerical studies 32,35 , but substantially smaller than Efros' analytical estimate 2/π 28 . The standard Coulomb gap shows up in transport as a stretched exponential resistance of the form…”

Section: Modelsupporting

confidence: 87%

“…W ≫ e 2 /a, where a is the typical distance between neighboring electrons. In that case, the Coulomb gap is theoretically predicted 30,31 and empirically found 32 to be essentially universal at low energies: ρ(E) exhibits linear variation, ρ(E) = α e 4 |E|. The co-efficient α is basically independent of the type of lattice, the filling fraction, and the details of the disorder 33,34 .…”

Section: Modelmentioning

confidence: 93%

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Two-component Coulomb glass in insulators with a local attraction

et al. 2012

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Motivated by evidence of local electron-electron attraction in experiments on disordered insulating films, we propose a new two-component Coulomb glass model that combines strong disorder and long-range Coulomb repulsion with the additional possibility of local pockets of a short-range interelectron attraction. This model hosts a variety of interesting phenomena, in particular a crucial modification of the Coulomb gap previously believed to be universal. Tuning the short-range interaction to be repulsive, we find non-monotonic humps in the density of states within the Coulomb gap. We further study variable-range hopping transport in such systems by extending the standard resistor network approach to include the motion of both single electrons and local pairs. In certain parameter regimes the competition between these two types of carriers results in a distinct peak in resistance as a function of the local attraction strength, which can be tuned by a magnetic field.

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Section: Modelsupporting

confidence: 87%

Section: Modelmentioning

confidence: 93%

Two-component Coulomb glass in insulators with a local attraction

et al. 2012

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“…( 1) and (2) were derived for the case when the bare DOS, which is the DOS without Coulomb interactions, has a non-zero value at ǫ = 0. The primary method for quantitative, theoretical study of the Coulomb gap is through computer simulations [6][7][8][9][10][11][12][13][14], which mostly confirm the above results for the 1P-DOS. The most important experimental manifestation of the Coulomb gap is its effect on the variable range hopping conductivity σ, which as a consequence of the Coulomb gap obeys the law [4],…”

Section: Introductionsupporting

confidence: 57%

“…However, such strong, exponential depletion of the 1P-DOS was never seen in computer experiments [6][7][8][9][10][11][12][13][14]. For large simulated samples this is the case because computer simulations are not able to reach the ground state of the system or cannot enforce a sufficiently large number of higher-order stability criteria.…”

Section: Introductionmentioning

confidence: 99%

Coulomb gap in the one-particle density of states in three-dimensional systems with localized electrons

2011

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The one-particle density of states (1P-DOS) in a system with localized electron states vanishes at the Fermi level due to the Coulomb interaction between electrons. Derivation of the Coulomb gap uses stability criteria of the ground state. The simplest criterion is based on the excitonic interaction of an electron and a hole and leads to a quadratic 1P-DOS in the three-dimensional (3D) case. In 3D, higher stability criteria, including two or more electrons, were predicted to exponentially deplete the 1P-DOS at energies close enough to the Fermi level. In this paper we show that there is a range of intermediate energies where this depletion is strongly compensated by the excitonic interaction between single-particle excitations, so that the crossover from quadratic to exponential behavior of the 1P-DOS is retarded. This is one of the reasons why such exponential depletion was never seen in computer simulations.

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“…We conclude that our results reproduce Efros and Shklovskii's law, although they are also compatible with a steeper DOS, as obtained in ref. [62]. We would like to remark that the 1/2 exponent was obtained by Pollak through a powerful scaling argument that does not rely on conductivity being due to single‐electron jumps.…”

Section: Resultsmentioning

confidence: 99%

Numerical Simulations of Variable‐Range Hopping

Ortuño

Estellés-Duart

Somoza

2021

Physica Status Solidi (b)

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Numerical simulations of variable‐range hopping in 2D and 3D systems with states localized by the disorder are reviewed. Both interacting and noninteracting systems are considered. After reviewing the main theories for variable‐range hopping, Mott's and Efros and Shkolvskii's, the numerical techniques are presented that are employed for this problem. Existing results are presented and some new ones obtained for this contribution, concentrating on the value of the proportionality constant on the characteristic temperatures of the different conduction laws and on the form of the pre‐exponential factor.

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Coulomb gap revisited – a renormalisation approach

Cited by 7 publications

References 5 publications

Two-component Coulomb glass in insulators with a local attraction

Two-component Coulomb glass in insulators with a local attraction

Coulomb gap in the one-particle density of states in three-dimensional systems with localized electrons

Numerical Simulations of Variable‐Range Hopping

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