Noncollinear interlayer coupling across a semiconductor spacer

Abstract

Based on the extended s-d exchange model, which includes both isotropic and anisotropic spin interactions between conduction electrons and local states, we have derived analytically the interlayer coupling across a semiconductor spacer with a general band structure. Both Heisenberg-type and Dzyaloshinski-Moriya ͑DM͒ -type Ruderman-Kittel-Kasuya-Yosida-like interlayer coupling are obtained as a result of spin-orbit interaction. The interlayer coupling decreases exponentially with spacer thickness and the oscillation period depends on the band structure and orientation of spacers. Our result is different from previous theory; in particular, the DM-type interlayer exchange coupling offers a natural explanation to the noncollinear alignment of neighboring ferromagnetic layers as were observed in recent experiments on magnetic-semiconductor multilayer structures.

Superexchange coupling in iron/silicon layered structures

“…Both these models predict the AFM character and exponential decay of J 1 ͑L͒, as the spacer thickness L increases. However, as was shown within the extended s-d exchange model, 19 the IEC decrease could be either monotonic or oscillatory ͑from FM to AFM coupling͒ function of L, depending on the band structure and crystalline orientation of the semiconductor spacer. The authors of Ref.…”