Antiferromagnetic coupling driven by bond length contraction near the Ga1-xMnxN film surface.
Using first principles calculations based on gradient corrected density functional theory we show that Mn atoms, which couple ferromagnetically in bulk Ga1-xMnxN, couple antiferromagnetically on its surface. This change in magnetic behavior is brought about by a contraction of the Mn-Mn and Mn-N bond lengths, which is significantly greater on the surface than in the bulk. The present study provides new insight to the numerous conflicting experimental observations in Mn doped GaN systems.
Wang
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Q
Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA.
Sun
Q
Q
Jena
P
P
Kawazoe
Y
Y