Electron-electron interaction effects in quantum point contacts

Abstract

We consider electron-electron interaction effects in quantum point contacts on the first quantization plateau, taking into account all scattering processes. We compute the low-temperature linear and nonlinear conductance, shot noise, and thermopower, by perturbation theory and a self-consistent nonperturbative method. On the conductance plateau, the low-temperature corrections are solely due to momentum-nonconserving processes that change the relative number of left- and right-moving electrons. This leads to a suppression of the conductance for increasing temperature or voltage. The size of the suppression is estimated for a realistic saddle-point potential, and is largest in the beginning of the conductance plateau. For large magnetic field, interaction effects are strongly suppressed by the Pauli principle, and hence the first spin-split conductance plateau has a much weaker interaction correction. For the nonperturbative calculations, we use a self-consistent nonequilibrium Green's function approach, which suggests that the conductance saturates at elevated temperatures. These results are consistent with many experimental observations related to the so-called 0.7 anomaly.

29 pages, New Journal of Physics, in press

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Cited by in corpus (22)

• Interacting topological edge channels
• Interaction induced edge channel equilibration
• Transport properties of partially equilibrated quantum wires
• Transport in partially equilibrated inhomogeneous quantum wires
• Statistical study of conductance properties in one-dimensional quantum wires focussing on the 0.7 anomaly
• Electron-electron scattering and magnetoresistance of ballistic microcontacts
• Steady-state properties of a thermodynamically unbalanced Fermi gas
• Origins of conductance anomalies in a p-type GaAs quantum point contact
• Effect of spin-orbit interactions on the 0.7 anomaly in quantum point contacts
• Functional Renormalization Group Approach for Inhomogeneous One-Dimensional Fermi Systems with Finite-Ranged Interactions
• Dependence of the 0.7 anomaly on the curvature of the potential barrier in quantum wires
• Statistical theory of relaxation of high energy electrons in quantum Hall edge states
• Fluctuation-driven Coulomb drag in interacting quantum dot systems
• The effect of split gate size on the electrostatic potential and 0.7 anomaly within one-dimensional quantum wires on a modulation doped GaAs/AlGaAs heterostructure
• Transconductance and effective Landé factors for quantum point contacts: spin-orbit coupling and interaction effects
• Mixed-order symmetry-breaking quantum phase transition far from equilibrium
• Spin-orbit coupling and resonances in the conductance of quantum wires
• Enhancement mechanism of the electron g-factor in quantum point contacts
• Electron-Electron scattering and resistivity of ballistic multimode channels
• Coherent Electron Optics with Ballistically Coupled Quantum Point Contacts
• Transmission-phase of an electron in a quantum point contact
• Functional Renormalization Group treatment of the 0.7-analog in quantum point contacts