STUDY ON MOMENTUM DENSITY IN NARROW-GAP MIXED III-V ALLOYS BY POSITRON-ANNIHILATION UNDER PRESSURE

The pressure dependence of the electron-positron momentum density in I nAsxSb1 - x was studied. The computational technique used here is base d on the independent particle model coupled with the use of the electr on pseudo-wave functions. The variation of the momentum density versus pressure is weak and snows that InAsxSb1 - x exhibits a more metallic character. The observation that the calculated total positron annihil ation rate increases with pressure has been explained in terms of incr eased positron penetration into the ion cores. The obtained results ha ve an essential role in the determination of the electronic band struc ture of narrow gap mixed III-V alloys under pressure. (C) 1998 Elsevie r Science S.A. All rights reserved.