掺杂Sr_8CaRe_3Cu_4O_(24):一种可能具有半金属性和大的氧磁矩的材料

Robust half-metallic behavior and large oxygen magnetism in a perovskite cuprate

用密度泛函理论方法仔细研究了新型钙钛矿铜氧材料Sr8CaRe3Cu4O24的电子结构和磁性性质,发现掺杂将使得这种材料表现出非常奇特的性质:(1)用W或Mo替代Re,将使得材料变成半金属,同时它的磁转变温度仍然很高;(2)对Sr8CaRe3Cu4O24进行空穴掺杂,也将使它变为具有高磁转变温度的半金属材料.更为奇特的是,空穴掺杂将导致O原子上有很大的磁矩.因此,Sr8CaRe3Cu4O24很有可能是一种有广阔应用前景的磁性材料.

The new perovskite cuprate material Sr8CaRe3Cu4O24, which behaves ferrimagnetically and shows an unusually high Curie temperature （Tc =440 K） , is found from density-functional theory calculation to display several surprising properties after hole doping or chemical substitution. Half- metal behavior is realized by replacing Re with W or Mo while Tc remains high. The hole- doped Sr8CaRe3Cu4O24is also a half- metal with high Tc. Moreover, we find that the O atoms will carry a large magnetic moment after hole doping, which is in sharp contrast to the generally accepted concept that magnetism in solids requires partially filled shells of d or f electrons in cations. The material Sr8CaRe3Cu4O24 is therefore expected to provide a very useful platform for material design and development.