Investigation of Possible Half-Metallic Antiferromagnets on Double Perovskites A_(2)BB′O_(6)(A=Ca,Sr Ba;B,B′=Transition Metal Elements)  

作　　者：S.H.Chen Z.R.Xiao Y.P.Liu Y.K.Wang 

机构地区：[1]Institute of Physics,Academia Sinica,Taipei 11529,Taiwan [2]Graduate Institute of Applied Physics,National Chengchi University,Taipei 11605,Taiwan [3]Department of Physics,National Taiwan Normal University,Taipei 106,Taiwan [4]Center for General Education and Department of Physics,National Taiwan Normal University,Taipei 106,Taiwan

出　　处：《Communications in Computational Physics》2013年第2期526-539,共14页计算物理通讯（英文）

基　　金：supports received from the National Science Council(99B0320);the National Center for Theoretical Sciences(NCTS),South Taiwan.

摘　　要：A search was made for possible half-metallic(HM)antiferromagnet(AFM)in all the(C_(2)^(92)=406)double perovskites structures of Sr2BB′O6 where BB′pairs are any combination of 3d,4d or 5d transition elements with the exception of La.Sr can also be replaced by Ca or Ba whenever HM-AFM was found and similar calculations were then performed in order to probe further possibilities.It was found that A_(2)MoOsO_(6),A_(2)TcReO_(6),A_(2)CrRuO_(6),where A=Ca,Sr,Ba,are all potential candidates for HM-AFM.The AFM of A2BB′O6 comes from both the superexchange mechanism and the generalized double exchange mechanism via the B(t2g)-O2pp-B′(t2g)coupling,With the latter also being the origin of their HM.Also considered were the effects of spin-orbit coupling(SOC)and correlation(+U)by introducing+SOC and+U corrections.It is found that the SOC effect has much less influence than the correlation effect on the HMproperty of the compounds.For A_(2)TcReO_(6)and A_(2)CrRuO_(6),after+U,they become nearlyMott-Insulators.In the future,it is hoped that therewill be further experimental confirmation for these possible HM-AFMcandidates.

关 键 词：Half-metal antiferromagnet GGA+U SUPEREXCHANGE generalized double exchange 

分 类 号：TG1[金属学及工艺—金属学]