摘要
报道了单晶石墨、多晶石墨电导行为的差异.在8.15T磁场下,4.5K处单、多晶石墨的正磁电阻效应分别为69400%,170%,同时在0T,8T磁场作用下,多晶石墨的电导行为呈现类绝缘体型性质,但在单晶石墨中我们发现了与磁场相关的类半金属-绝缘体型转变,通过分析,我们认为:单、多晶石墨电导行为存在较大差异的原因可能来源于库仑相互作用在高定向热解石墨中变得不可忽视,而多晶石墨样品却存在晶界散射.
In this paper, we report the difference in electric conduction of monocrystal and polycrystal graphite. Under a magnetic field of 8.15 T, the positive magnetoresistance ratio of monocrystal and polycrystal graphite samples are found to be 69400% , 170% respectively at 4.5 K. The polycrystal graphite presents accordingly the insulator-like character in a wide interval of temperature under 0 and 8 T applied magnetic field, but the magnetic-field-correlated semimetal-insulator-like Transition has been reported for the monocrystal graphite （highly oriented pyrolitic graphite, HOPG）. On analysis, it is revealed that large difference in electric conduction originates predominantly from the Coulomb interaction in HOPG graphite layers in contrast with the crystal interface scattering in the polycrystal graphite.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第6期3464-3467,共4页
Acta Physica Sinica
基金
南京大学固体微结构物理实验室开放课题(批准号:M041901)资助的课题~~
