A. J. Freeman — Page 3

arXiv1997

Effects of epitaxial strain and ordering direction on the electronic properties of (GaSb)_1/(InSb)_1 and (InAs)_1/(InSb)_1 superlattices

The structural and electronic properties in common anion (GaSb)_1/(InSb)_1 and common cation (InAs)_1/(InSb)_1 [111] ordered superlattices have been determined using the local density total energy full potential linearized augmented plane wave method. The influence of the ordering direction, strain conditions and atomic substitution on the electronic properties of technological and experimental interest (such as energy band-gaps and charge carrier localization in the different sublattices) were determined. The results show an appreciable energy band-gap narrowing compared to the band-gap averaged over the constituent binaries, either in [001] ordered structures or (more markedly) in the [111] systems; moreover energy band-gaps show an increasing trend as the substrate lattice parameter is decreased. Finally, the systems examined offer interesting opportunities for band-gap tuning as a function of the growth condition (about 0.7 eV in (GaSb)_1/(InSb)_1 and 0.3 eV in (InAs)_1/(InSb)_1).

cond-mat.mtrl-sci↗

arXiv1993

Effect of Structure on the Electronic Density of States of Doped Lanthanum Cuprate

We present a series of detailed band calculations on the various structural phases of doped lanthanum cuprate: HTT, LTO, and LTT. The LTO distortion is shown to have little effect on the electronic density of states (DOS). A fit to the pressure dependence of the superconducting transition temperature indicates that only 2.5% of the DOS is affected by the HTT$\to$ LTO transition. The LTT distortion also has little effect on the DOS for the experimental value of the octahedral tilt angle. Larger tilt angles, though, lead to a dramatic change in the DOS.

cond-mat↗