| Автор | Yolande H Szczech |
| Автор | Michael A Tusch |
| Автор | David E Logan |
| Дата выпуска | 1997-11-03 |
| dc.description | We study the collective excitation spectrum of a d = 3 site-disordered Anderson - Hubbard model at half-filling, via a random-phase approximation (RPA) about broken-symmetry, inhomogeneous unrestricted Hartree - Fock (UHF) ground states. We focus in particular on the density and character of low-frequency collective excitations in the transverse spin channel. In the absence of disorder, these are found to be spin-wave-like for all but very weak interaction strengths, extending down to zero frequency and separated from a Stoner-like band, to which there is a gap. With disorder present, a prominent spin-wave-like band is found to persist over a wide region of the disorder - interaction phase plane in which the mean-field ground state is a disordered antiferromagnet, despite the closure of the UHF single-particle gap. Site resolution of the RPA excitations leads to a microscopic rationalization of the evolution of the spectrum with disorder and interaction strength, and enables the observed localization properties to be interpreted in terms of the fraction of strong local moments and their site-differential distribution. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Collective excitation spectrum of a disordered Hubbard model |
| Тип | paper |
| DOI | 10.1088/0953-8984/9/44/017 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 9 |
| Первая страница | 9621 |
| Последняя страница | 9638 |
| Аффилиация | Yolande H Szczech; University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK |
| Аффилиация | Michael A Tusch; University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK |
| Аффилиация | David E Logan; University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK |
| Выпуск | 44 |
