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arXiv 0908.0303cond-mat.mtrl-scicond-mat.supr-con
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FeSe中无序效应的从头算研究

Effects of Disorder in FeSe : An Ab Initio Study

Prabhakar P Singh

摘要:

本文用相干势近似研究了FeSe中Fe的过量、Se的缺乏以及S、Te对Se亚晶格的替代和Co、Ni、Cu对Fe亚晶格的替代的影响。结果表明:(i)少量过量Fe使Fe导带发生无序化,而Se的缺乏主要影响Se导带;(ii)S或Te的替代增强了费米面嵌套的可能性,特别是在FeSe $_{0.5}$ Te $_{0.5}$中,尽管Se导带发生无序化;(iii)Co的电子掺杂,Ni或Cu使系统紊乱并向下推Fe衍生带,从而破坏费米表面嵌套的可能性。这些结果与刚性带,虚拟晶体和超原胞近似的比较揭示了与相干势近似描述无序的重要性。

英文摘要:

Using the coherent-potential approximation, we have studied the effects of excess Fe, Se-deficiency, and substitutions of S, Te on Se sub-lattice and Co, Ni and Cu on Fe sub-lattice in FeSe. Our results show that (i) a small amount of excess Fe substantially disorders the Fe-derived bands while Se-deficiency affects mainly the Se-derived bands, (ii) the substitution of S or Te enhances the possibility of Fermi surface nesting, specially in FeSe$_{0.5}$Te$_{0.5}$, in spite of disordering the Se-derived bands, (iii) the electron doping through Co, Ni or Cu disorders the system and pushes down the Fe-derived bands, thereby destroying the possibility of Fermi surface nesting. A comparison of these results with the rigid-band, virtual-crystal and supercell approximations reveals the importance of describing disorder with the coherent-potential approximation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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