Excitonic instabilities in semiconductor superlattices in the lowest Landau level

✍ Scribed by D.C. Marinescu; J.J. Quinn

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 86 KB
• Volume: 13
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(01)00556-2

✦ Synopsis

In a superlattice whose unit cell contains two identical quantum wells distanced by a length b, weak tunneling is allowed to occur both intra-and inter-cell. The intra-cell tunneling leads to the splitting of the electron energy levels in two minibands separated by S AS = ES -EAS, the symmetric-antisymmetric energy gap. The inter-cell tunneling broadens these minibands to a width proportional to the tunneling probability. In the presence of a magnetic ÿeld, when additional splitting of the energy levels occurs, a degeneracy between minibands of opposite spins can be realized by tuning the intensity of the magnetic ÿeld and the tunneling probability. Within the Hartree-Fock approximation, we investigate the existence of excitonic instabilities that can arise when, in the lowest Landau level (n = 0), the |S ↑ and |A ↓ minibands are almost degenerate. ? 2002 Published by Elsevier Science B.V.