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

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.

References in corpus (1)

• First principles investigation of transition-metal doped group-IV semiconductors: R${}_x$Y${}_{1-x}$ (R=Cr, Mn, Fe; Y=Si, Ge)

Cited by in corpus (4)

• Density-functional theory study of half-metallic heterostructures: interstitial Mn in Si
• A review of the electronic and magnetic properties of tetrahedrally bonded half-metallic ferromagnets
• Ferromagnetism in Nitrogen-doped MgO
• Optimization of Mn Doping in Group-IV-based Dilute Magnetic Semiconductors by Electronic Co-dopants