Electronic structure and exchange constants in magnetic semiconductor digital alloys: chemical and band-gap effects

✍ Scribed by Picozzi, S. ;Ležaić, M. ;Blügel, S.

• Book ID: 105364023
• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 268 KB
• Volume: 203
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200669574

✦ Synopsis

Abstract

First‐principles simulations have been performed for [001]‐ordered Mn/Ge and Mn/GaAs “digital alloys”, focusing on the effects of (i) a larger band‐gap and (ii) a different semiconducting host on the electronic structure of the magnetic semiconductors of interest. Our results for the exchange constants in Mn/Ge, evaluated using a frozen‐magnon scheme, show that a larger band‐gap tends to give a stronger nearest‐neighbor ferromagnetic coupling and an overall enhanced in‐plane ferromagnetic coupling even for longer‐ranged coupling constants. As for the chemical effects on the exchange constants, we show that Mn/GaAs shows a smaller nearest‐neighbor ferromagnetic coupling than Mn/Ge, but exchange constants for higher Mn–Mn distance show an overall increased ferromagnetic behavior in Mn/GaAs. As a result, from the magnetic‐coupling point of view, the two systems behave on average rather similarly. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)