Open AccessПереход между электронной локализацией и антилокализацией, а также проявление фазы Берри в графене на поверхности SiC
Author(s) -
Н.В. Агринская,
А.А. Лебедев,
С.П. Лебедев,
М.А. Шахов,
E. Lähderanta
Publication year - 2018
Publication title -
fizika i tehnika poluprovodnikov
Language(s) - English
Resource type - Journals
eISSN - 1726-7315
pISSN - 0015-3222
DOI - 10.21883/ftp.2018.12.46767.8892
Subject(s) - weak localization , magnetoresistance , condensed matter physics , graphene , electron , physics , magnetic field , geometric phase , effective mass (spring–mass system) , materials science , quantum mechanics
It is shown that the transport properties of graphitized silicon carbide are controlled by a surface graphene layer heavily doped with electrons. In weak magnetic fields and at low temperatures, a negative magnetoresistance is observed due to weak localization. A crossover in the magnetoresistance from weak localization to weak antilocalization (the latter is the manifestation of the isospin in graphene) is observed for the first time in samples of this kind at elevated temperatures. A pronounced pattern of Shubnikov–de Haas oscillations is observed in strong magnetic fields (up to 30 T). This pattern demonstrated fourfold carrier spectrum degeneracy due to the double spin and double valley degeneracies. Also, the manifestation of the Berry phase is observed. The effective electron mass is estimated to be m * = 0 . 08 m _0, which is characteristic of graphene with a high carrier concentration.