IOP PUBLISHING JOURNAL OF PHYSICS: CONDENSED MATTER J. Phys.: Condens. Matter 20 (2008) 164217 (17pp) doi:10.1088/0953-8984/20/16/164217 Electron interaction and spin effects in quantum wires, quantum dots and quantum point contacts: a first-principles mean-field approach I V Zozoulenko and S Ihnatsenka Solid State Electronics, Department of Science and Technology (ITN), Link¨ oping University, 60174 Norrk¨ oping, Sweden Received 5 October 2007, in final form 14 November 2007 Published 1 April 2008 Online at stacks.iop.org/JPhysCM/20/164217 Abstract We have developed a mean-field first-principles approach for studying electronic and transport properties of low dimensional lateral structures in the integer quantum Hall regime. The electron interactions and spin effects are included within the spin density functional theory in the local density approximation where the conductance, the density, the effective potentials and the band structure are calculated on the basis of the Green’s function technique. In this paper we present a systematic review of the major results obtained on the energetics, spin polarization, effective g factor, magnetosubband and edge state structure of split-gate and cleaved-edge overgrown quantum wires as well as on the conductance of quantum point contacts (QPCs) and open quantum dots. In particular, we discuss how the spin-resolved subband structure, the current densities, the confining potentials, as well as the spin polarization of the electron and current densities in quantum wires and antidots evolve when an applied magnetic field varies. We also discuss the role of the electron interaction and spin effects in the conductance of open systems focusing our attention on the 0.7 conductance anomaly in the QPCs. Special emphasis is given to the effect of the electron interaction on the conductance oscillations and their statistics in open quantum dots as well as to interpretation of the related experiments on the ultralow temperature saturation of the coherence time in open dots. (Some figures in this article are in colour only in the electronic version) 1. Introduction Electron–electron interaction is known to have a great impact on electronic and transport properties of low dimensional structures such as quantum wires, quantum point contacts, quantum dots and antidots. This includes such pronounced examples as Coulomb blockade [1] and Kondo effect [2] in quantum dots, exchange enhancement of the g-factor [3] and a spatial spin separation on wire edges in the quantum Hall regime [4], the ‘0.7-anomaly’ in quantum point contacts [5] and many others. Theoretical description of electron interactions in the above systems can be performed from many different standpoints, including field-theoretical approaches, exact numerical techniques, perturbation methods, mean-field theories etc. Very often this description is based on model Hamiltonians containing phenomenological parameters of the theory such as coupling strengths or charging constants. In many cases it is not always straightforward to relate quantitatively the above parameters to the physical processes they represent in the real system and sometimes it is not even obvious whether a model description is sufficient to capture the essential physics. At the same time, it is now well recognized that a detailed understanding and interpretation of experiments might require quantitative microscopical modeling of the system at hand, free from phenomenological parameters and not relying on model Hamiltonians which validity is poorly controlled. The importance of such modeling can be illustrated by examples including the quantitative description of the compressible and/or incompressible strips in magnetic field 0953-8984/08/164217+17$30.00 © 2008 IOP Publishing Ltd Printed in the UK 1