Coulomb gap in a doped semiconductor near the metal-insulator transition: Tunneling experiment and scaling ansatz

Lee, Mark; Massey, J. G.; Nguyen, V. Lien; Shklovskiǐ, B. I.

doi:10.1103/physrevb.60.1582

Cited by 72 publications

(105 citation statements)

References 45 publications

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“…The systematic scaling of T 0 with V G likely reflects the divergence hopping length, as expected near the metal-insulator transition. 23,24 This further confirms the interpretation that the gate voltage tunes the channel in proximity to the metal-insulator transition.…”

Section: à2supporting

confidence: 80%

Electric field effect near the metal-insulator transition of a two-dimensional electron system in SrTiO3

Ahadi

Shoron

Marshall

et al. 2017

Applied Physics Letters

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SmTiO3/SrTiO3 interfaces exhibit a two-dimensional electron system with carrier densities in the order of 3 × 1014 cm−2 due to the polar discontinuity at the interface. Here, electric field effect is used to investigate an electron system at this interface whose carrier density has been depleted substantially by the gate metal and by reducing the thickness of the SmTiO3. At zero applied gate voltage, the sheet resistance exceeds the quantum resistance, h/e2, by more than an order of magnitude, and the SrTiO3 channel is in the hopping transport regime. The electric field modulates the carrier density in the channel, which approaches the transition to a metal at positive gate bias. The channel resistances are found to scale by a single parameter that depends on the gate voltage, similar to two-dimensional electron systems in high-quality semiconductors.

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Section: à2supporting

confidence: 80%

Electric field effect near the metal-insulator transition of a two-dimensional electron system in SrTiO3

Ahadi

Shoron

Marshall

et al. 2017

Applied Physics Letters

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“…In the last ten years, several tunneling experiments on weakly insulating samples provided direct evidence for a pseudogap in the density of states around the Fermi level 40,41,42,43,44,45,46,47 . However, such experiments are restricted to the regime relatively close to the metalinsulator transition.…”

Section: B Coulomb Gap and Hopping Transportmentioning

confidence: 99%

Memory effect in electron glasses: Theoretical analysis via a percolation approach

Lebanon

Müller

2005

Phys. Rev. B

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We present a theory for the memory effect in electron glasses. In fast gate voltage sweeps it is manifested as a dip in the conductivity around the equilibration gate voltage. We show that this feature, also known as anomalous field effect, arises from the long-time persistence of correlations in the electronic configuration. We argue that the gate voltage at which the memory dip saturates is related to an instability caused by the injection of a critical number of excess carriers. This saturation threshold naturally increases with temperature. On the other hand, we argue that the gate voltage beyond which memory is erased, is temperature independent. Using standard percolation arguments, we calculate the anomalous field effect as a function of gate voltage, temperature, carrier density and disorder. Our results are consistent with experiments, and in particular, they reproduce the observed scaling of the width of the memory dip with various parameters.

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“…[4] tunneling Ref. [30] σ DC this work 30 and the data represented by the full diamonds is adapted from AC conductivity network analyzer measurements performed in a dilution refrigerator 3 . Both measurements were done on Si:B, a disordered insulator analogous to Si:P. Our measured crossover frequencies 4 are represented by the full circles and our experimentally determined crossover temperatures are converted to frequency and are represented by the crossed squares.…”

Section: B Ac Transport and Polarizability: The Crossovermentioning

confidence: 99%

Frequency-dependent conductivity of electron glasses

2004

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Results of DC and frequency dependent conductivity in the quantum limit, i.e.hω > kBT , 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.

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Coulomb gap in a doped semiconductor near the metal-insulator transition: Tunneling experiment and scaling ansatz

Cited by 72 publications

References 45 publications

Electric field effect near the metal-insulator transition of a two-dimensional electron system in SrTiO3

Electric field effect near the metal-insulator transition of a two-dimensional electron system in SrTiO3

Memory effect in electron glasses: Theoretical analysis via a percolation approach

Frequency-dependent conductivity of electron glasses

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