Interplay between double-exchange, superexchange, and Lifshitz localization in doped manganites -: art. no. 104430

被引:39
作者
Alonso, JL [1 ]
Fernández, LA
Guinea, F
Laliena, V
Martín-Mayor, V
机构
[1] Univ Zaragoza, Fac Ciencias, Dept Fis Teor, E-50009 Zaragoza, Spain
[2] Univ Complutense Madrid, Fac Ciencias Fis, Dept Fis Teor, E-28040 Madrid, Spain
[3] CSIC, Inst Ciencia Mat, E-28049 Madrid, Spain
[4] Univ Roma La Sapienza, Dipartimento Fis, Ist Nazl Fis Nucl, SMC, I-00185 Rome, Italy
[5] INFM, UdR1, I-00185 Rome, Italy
关键词
D O I
10.1103/PhysRevB.66.104430
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Considering the disorder caused in manganites by the substitution Mn-->Fe or Ga, we accomplish a systematic study of doped manganites begun in previous papers. To this end, a disordered model is formulated and solved using the variational mean-field technique. The subtle interplay between double exchange, superexchange, and disorder causes similar effects on the dependence of T-C on the percentage of Mn substitution in the cases considered. Yet, in La2/3Ca1/3Mn1-yGayO3 our results suggest a quantum critical point (QCP) for yapproximate to0.1-0.2, associated to the localization of the electronic states of the conduction band. In the case of LaxCaxMn1-yFeyO3 (with x=1/3,3/8) no such QCP is expected.
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页码:1 / 6
页数:6
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