Interatomic exchange in Mn-doped III-V semiconductors

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:324

Article

Sharma, Vinit¹  Manchanda, Priyanka¹  Sahota, Pankaj K.¹  Skomski, Ralph^2,3  Kashyap, Arti¹ 

[1] LNM Inst Informat Technol, Condensed Matter Theory Grp, Jaipur 302031, Rajasthan, India

[2] Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68508 USA

[3] Univ Nebraska, NCMN, Lincoln, NE 68508 USA

关键词: Magnetic semiconductor;    First-principle calculation;    Exchange interaction;   

DOI  :  10.1016/j.jmmm.2011.09.017

来源: Elsevier

【 摘 要 】

Density-functional calculations are used to determine the electronic structure and magnetic properties of dilute magnetic semiconductors with the composition X1-xMnxN (X=Al, Ga, In, x=6.25% and 12.5%). Emphasis is on the interatomic exchange as a function of the Mn-Mn distance. Our superlattice calculations show that the Mn dopants are spin-polarized with a half-metallic band gap and a magnetic moment of 4 mu(B) per Mn atom at x=6.25 and 12.5%. The Mn (3d) bands lie in the band gap but partially hybridize with valence band or N 2p electrons, depending on the group-III element and on the spin direction. To calculate the exchange interaction parameters J(y), we have used a Green-function approach. The interaction between Mn atoms extends over several interatomic interactions and is mediated by nitrogen (2p) electrons. The exchange is always ferromagnetic and largest for the first nearest neighbors, but substantial ferromagnetic interactions persist over Mn-Mn distances up to sixth nearest neighbors in the considered supercell. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

Free