中国科学技术大学高温超导物理研究新进展  

High-T_c superconductivity research in the University of Science and Technology of China

作　　者：陈仙辉[1] 

机构地区：[1]中国科学技术大学物理系合肥微尺度物质科学国家实验室,合肥230026

出　　处：《物理》2008年第8期568-572,共5页Physics

摘　　要：在中国科学技术大学(以下简称中国科大)建校50周年之际,文章作者对近年来中国科大在高温超导物理方面的最新研究进展情况作一介绍,包括新型高温超导材料探索研究和高温超导机理实验研究.在新型高温超导材料探索研究方面,文章作者首次发现了除高温超导铜基化合物以外第一个超导温度突破麦克米兰极限(39K)的非铜基超导体——铁基砷化物SmO1-xFxFeAs,该类材料的最高超导转变温度可达到55K;中国科大还成功地制备出大量高质量的超导化合物单晶,包括Nd2-xCexCuO4,NaxCoO2,CuxTiSe2等.在高温超导机理实验研究方面,中国科大系统地研究了SmO1-xFxFeAs体系的电输运性质给出了该体系的电子相图;发现了在电子型高温超导体中存在反常的热滞现象和电荷-自旋强烈耦合作用;在NaxCoO2体系中也开展了系列的工作,并且首次明确了电荷有序态中小自旋的磁结构问题;此外,还系统地研究了CuxTiSe2体系中电荷密度波与超导的相互关系.To celebrate the 50th anniversary of the founding of the University of Science and Technology of China, a brief review is presented of recent research on high-Tc superconductivity there. The search for new high-Tc materials and experimental research on the mechanism of high-Tc superconductivity led to our discovery of the Febased arsenide superconductor SmO1-x FxFeAs, which is the first non-copper-oxide superconductor with a transition temperature beyond the McMillan limit （39 K）, while the highest transition temperature in this system can reach 55 K. A variety of superconducting single crystals including Nd2 _xCexCuO4, NaxCoO2 and CuxTiSe2 have been successfully grown. To understand the mechanism of high-Tc superconductivity we have systematically studied the electronic transport of the SmO1-xFxFeAs system and proposed a corresponding electronic phase diagram. Abnormal thermal hysteresis and spin-charge coupling have been found in electron-type high-Tc superconductors. In the Nax CoO2 system the magnetic structure of the small magnetic moment in the charge ordered state has been clarified. The relationship between charge density waves and superconductivity in the CuxTiSe2 system has also been studied.

关 键 词：高温超导 铁基砷化物 自旋-电荷耦合 电荷有序 电荷密度波 

分 类 号：O511[理学—低温物理] O469[理学—物理]