The electron tunneling is experimentally studied between two-dimensional electron gases (2DEGs) formed in a single-doped-barrier heterostructure in the magnetic fields directed perpendicular to the 2DEGs planes. It is well known that the quantizing magnetic field induces the Coulomb pseudogap suppressing the electron tunneling at Fermi level. In this paper we firstly present the experimental results revealing the pseudogap in the electron tunneling assisted by elastic electron scattering on disorder.
Tunnelling between two-dimensional electron systems has been studied in the magnetic field perpendicular to the systems planes. The satellite conductance peaks of the main resonance have been observed due to the electron tunnelling assisted by the elastic scattering on impurities in the barrier layer. These peaks are shown to shift to the higher voltage due to the Coulomb pseudogap in the intermediate fields. In the high magnetic fields the pseudogap shift is disappeared.
We show that, in a magnetic field parallel to the 2D electron layer, strong electron correlations change the rate of tunneling from the layer exponentially. It results in a specific density dependence of the escape rate. The mechanism is a dynamical Mossbauer-type recoil, in which the Hall momentum of the tunneling electron is partly transferred to the whole electron system, depending on the interrelation between the rate of interelectron momentum exchange and the tunneling duration. We also show that, in a certain temperature range, magnetic field can enhance rather than suppress the tunneling rate. The effect is due to the magnetic field induced energy exchange between the in-plane and out-of-plane motion. Magnetic field can also induce switching between intra-well states from which the system tunnels, and a transition from tunneling to thermal activation. Explicit results are obtained for a Wigner crystal. They are in qualitative and quantitative agreement with the relevant experimental data, with no adjustable parameters.
The lifetime of two dimensional electrons in GaAs quantum wells, placed in weak quantizing magnetic fields, is measured using a simple transport method in broad range of temperatures from 0.3 K to 20 K. The temperature variations of the electron lifetime are found to be in good agreement with conventional theory of electron-electron scattering in 2D systems.
We consider the effect of electron correlations on tunneling from a 2D electron layer in a magnetic field parallel to the layer. A tunneling electron can exchange its momentum with other electrons, which leads to an exponential increase of the tunneling rate compared to the single-electron approximation. Explicit results are obtained for a Wigner crystal. They provide a qualitative and quantitative explanation of the data on electrons on helium. We also discuss tunneling in semiconductor heterostructures.
In this paper we develop the theory for 2D-to-2D tunneling spectroscopy aided by magnetic or quantum-order excitations, and apply it to the description of van-der-Waals heterostructures of graphene/ultrathin $alpha-{rm RuCl}_3$. We study the behavior of both the differential conductance and the inelastic electron tunneling spectrum (IETS) of these heterostructures. The IETS in particular exhibits features, such as the gap of continuum spinon excitations and Majorana bound states, whose energies scale {it cubicly} with the applied magnetic field. Such scaling, which exists for a relatively wide range of fields, is at odds with the linear one exhibited by conventional magnons and can be used to prove the existence of Kitaev quantum spin liquids.
V. G. Popov
,O. N. Makarovskii
,V. Renard
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(2008)
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"Coulomb pseudogap in elastic 2D-2D electron tunneling in a quantizing magnetic field"
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Vladimir Popov G.
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