Electron transport through quantum wires and point contacts

Abstract

We have studied quantum wires using the Green's function technique and the density-functional theory, calculating the electronic structure and the conductance. All the numerics are implemented using the finite-element method with a high-order polynomial basis. For short wires, i.e. quantum point contacts, the zero-bias conductance shows, as a function of the gate voltage and at a finite temperature, a plateau at around 0.7G_0. (G_0 = 2e^2/h is the quantum conductance). The behavior, which is caused in our mean-field model by spontaneous spin polarization in the constriction, is reminiscent of the so-called 0.7-anomaly observed in experiments. In our model the temperature and the wire length affect the conductance-gate voltage curves in the same way as in the measured data.

8 pages

References in corpus (12)

• First-Principles Based Matrix-Green's Function Approach to Molecular Electronic Devices: General Formalism
• Possible Spin Polarization in a One-Dimensional Electron Gas
• Correlation energy and spin polarization in the 2D electron gas
• The Low-Temperature Fate of the 0.7 Structure in a Point Contact: A Kondo-like Correlated State in an Open System
• Interaction Effects in a One-Dimensional Constriction
• Kondo model for the "0.7 anomaly" in transport through a quantum point contact
• Bias and temperature dependence of the 0.7 conductance anomaly in Quantum Point Contacts
• Density dependent spin polarisation in ultra low-disorder quantum wires
• Many-body spin related phenomena in ultra-low-disorder quantum wires
• Local moment formation in quantum point contacts
• Non-Equilibrium Electron Transport in Two-Dimensional Nano-Structures Modeled by Green's Functions and the Finite-Element Method
• Detection of local-moment formation using the resonant interaction between coupled quantum wires

Cited by in corpus (15)

• What lurks below the last plateau: Experimental studies of the 0.7 x 2e^2/h conductance anomaly in one-dimensional systems
• Three real-space discretization techniques in electronic structure calculations
• Spin dependent electron transport through a magnetic resonant tunneling diode
• Localization in an Inhomogeneous Quantum Wire
• Conductance of a quantum point contact based on spin-density-functional theory
• Low Rank Approximation Method for Efficient Green's Function Calculation of Dissipative Quantum Transport
• Nonequilibrium thermodynamics of interacting tunneling transport: variational grand potential, density-functional formulation, and nature of steady-state forces
• Ground state structure and conductivity of quantum wires of infinite length and finite width
• Tunable 0.7 conductance plateau in quantum dots
• Temperature Modulation of the Transmission Barrier in Quantum Point Contacts
• 0.4 and 0.7 conductance anomalies in quantum point contacts
• Hysteresis in the Conductance of Asymmetrically Biased GaAs Quantum Point Contacts with in-plane Side Gates
• Nuclear magnetic resonance probes for the Kondo scenario for the 0.7 feature in semiconductor quantum point contact devices
• Intrinsic Bistability In Quantum Point Contacts with in-plane Side Gates
• Impact of the non-canonical approach to the exact solution of the ideal one-dimensional electron gas confined with an anisotropic quantum wire of oscillator-shaped profile