Collective Excitations in Realistic Quantum Wires

TL;DR

This study uses HF-RPA to analyze collective spin and charge excitations in quantum wires, revealing significant shifts and renormalizations due to exchange interactions, with results aligning well with experiments.

Contribution

It provides a detailed theoretical analysis of collective excitations in quantum wires using HF-RPA, highlighting exchange effects and comparing with experimental data.

Findings

Red shift in intersubband spin-flip excitations

Linear dispersion of intrasubband spin-density excitations with renormalized velocities

Long wavelength charge-density excitation follows q[-ln(q)]^{1/2} form

Abstract

We have used the Hartree-Fock Random Phase Approximation (HF-RPA) to study the interacting electron gas in a quantum wire. The spectra of intersubband spin-flip excitations reveal a considerable red shift with respect to single-particle HF energies. That signals on appearance of collective intersubband spind-density excitations due to the exchange interaction. The long wavelength dispersions of the intrasubband collective spin-density excitations are linear, but the sound velocities are renormalised due to the exchange interaction and screening. The in-phase intrasubband charge-density excitation has the long wavelength form $q[-\ln(q)]^{1/2}$. We found good qualitative agreement of our results with experimental observations.