Magnetoconductance of interacting electrons in quantum wires: Spin density functional theory study

TL;DR

This study uses spin density functional theory to quantitatively analyze the magnetoconductance of quantum wires, revealing spin-resolved conductance plateaus and explaining experimental observations including plateau collapse at low magnetic fields.

Contribution

It provides a detailed spin DFT-based analysis of quantum wire conductance, highlighting the role of exchange-correlation interactions and matching experimental data.

Findings

Spin degeneracy is lifted, forming spin-resolved conductance plateaus.

Width of odd conductance steps matches transition intervals in spinless models.

Reproduces experimental features, including plateau collapse at low fields.

Abstract

We present systematic quantitative description of the magnetoconductance of the split-gate quantum wires. Accounting for the exchange and correlation interactions within the spin density function theory (DFT) leads to the lifting of the spin degeneracy and formation of the spin-resolved plateaus at odd values of $e^{2}/h$. We show that the width of the odd conductance steps in the spin DFT calculations is equal to the width of the transition intervals between the conductance steps for the spinless electrons in the Hartree approximation. A detailed analysis of the structure of compressible/incompressible strips and the evolution of the Hartree and the spin-DFT subband structure provides an explanation of this finding. Our spin-DFT calculations reproduce not only qualitatively, but rather quantitatively all the features in the magnetoconductance observed in the recent experiment (I. P. Radu, J. B. Miller, S. Amasha, E. Levenson-Falk, D. M. Zumbuhl, M. A. Kastner, C. M. Marcus, L. N. Pfeiffer, and K. W. West, to be published) including the unexpected effect of the collapse of the odd conductance plateaus at lower fields.