Trends of exchange interactions in dilute magnetic semiconductors
Trends of exchange interactions in dilute magnetic semiconductors
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DOI：
10.1088/0953-8984/19/43/436227
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发表时间：
2007-10-31
影响因子：
2.7
通讯作者：
Katayama-Yoshida, H.
中科院分区：
文献类型：
--
作者：
Belhadji, B.;Bergqvist, L.;Katayama-Yoshida, H.
讨论了双交换、p-d交换、反铁磁交换和铁磁超交换等不同交换机制在稀磁半导体中的重要性。基于相干势近似的DMS的电子结构，我们表明，不同的机制表现出不同的依赖于磁性杂质的浓度，与相邻杂质的波函数的杂化和费米能级的带隙中的位置。然而，所有机制的共同之处在于，只要保留半金属性，它们就由与相邻杂质的轨道的杂化以及由于形成成键和反键杂化物而产生的能量增益来确定。通过计算交换耦合常数J（ij）（E-F）随费米能级位置的变化，得到了交换相互作用随能带填充的普遍趋势。
We discuss the importance of different exchange mechanisms like double exchange, p-d exchange and anti-ferromagnetic as well as ferromagnetic superexchange in dilute magnetic semiconductors (DMSs). Based on the coherent potential approximation for the electronic structure of the DMSs we show that the different mechanisms exhibit different dependences on the concentration of the magnetic impurities, on the hybridization with the wavefunctions of neighbouring impurities and on the position of the Fermi level in the band gap. However, common to all mechanisms is that, as long as half-metallicity is preserved, they are determined by the hybridization with the orbitals of neighbouring impurities and of the resulting energy gain due to the formation of bonding and anti-bonding hybrids. By calculating the exchange coupling constants J(ij) (E-F) as a function of the position of the Fermi level we obtain a universal trend for the exchange interactions with band filling.