Varelogiannis G
Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Strasse 38, 01187 Dresden, Germany.
Phys Rev Lett. 2000 Nov 6;85(19):4172-5. doi: 10.1103/PhysRevLett.85.4172.
We report a multicomponent theory for the coexistence of charge ordering (CO), and antiferromagnetic (AFM) and ferromagnetic (FM) spin ordering. This kind of state is invoked for manganites by Moreo et al., Science 283, 2034 (1999) and observed in recent experiments. We show that doping an AFM or CO state always generates a FM component. FM, AFM, and CO necessarily coexist in a particle-hole asymmetric system. Melting of large AFM-CO orders by small magnetic fields and colossal magnetoresistance (CMR) arise whenever the CO and AFM order parameters have similar magnitude and momentum structure. Hole doping favors FM metallic states while electron doping favors AFM-CO states, as in CMR manganites.
我们报告了一种关于电荷有序（CO）、反铁磁（AFM）和铁磁（FM）自旋有序共存的多组分理论。莫雷奥等人（《科学》283, 2034 (1999)）针对锰氧化物提出了这种状态，并在最近的实验中观察到。我们表明，对AFM或CO态进行掺杂总会产生一个FM组分。在粒子 - 空穴不对称系统中，FM、AFM和CO必然共存。只要CO和AFM序参量具有相似的大小和动量结构，小磁场就能使大的AFM - CO序熔化，并产生巨磁电阻（CMR）。与CMR锰氧化物一样，空穴掺杂有利于FM金属态，而电子掺杂有利于AFM - CO态。
