Room-temperature quantum Hall effect in graphene: the role of the two-dimensional nature of phonons

27th International Conference on Low Temperature Physics

Greshnov, A.A.^1,2

Ioffe Physical-Technical Institute RAS, Polytechnicheskaya 26, St-Petersburge, Russia^1

Saint Petersburg Electrotechnical University, Professora Popova 5, St-Petersburge, Russia^2

关键词: Acoustic phonons;    Electron phonon couplings;    High temperature;    Magnetic length;    Percolation thresholds;    Two dimensional nature;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/5/052010/pdf
DOI  :  10.1088/1742-6596/568/5/052010

来源: IOP

【 摘 要 】

We consider two-dimensional nature of the electron-phonon coupling in graphene as a source for the room-temperature quantum Hall effect discovered in 2007. It is shown that magnetic field introduces strong cut-off for coupling with the two-dimensional acoustic phonons, viz. The processes with energy tranfer exceeding hslB-1are exponentially suppressed, while for three-dimensional phonons the cut-off is set by a temperature T (here s is the sound velocity and lB∝ B-1/2is the magnetic length). Consequently, at sufficiently high temperatures and magnetic fields only a small part (∼ hslB-1/T) of the electron states is involved in coupling with a given electron state in comparison with the case of three-dimensional phonons. Hence, the percolation threshold is postponed, and the quantum Hall effect survives up to T 300 K.