Disorder and de-coherence in graphene probed by low-temperature magneto-transport: weak localization and weak antilocalization

20th International Conference on the Application of High Magnetic Fields in Semiconductor Physics

Pezzini, S.^1,2 ; Cobaleda, C.^2 ; Diez, E.^2 ; Bellani, V.^1

Dipartimento di Fisica and CNISM, Università Degli Studi di Pavia, I-27100 Pavia, Italy^1

Laboratorio de Bajas Temperaturas, Universidad de Salamanca, E-37008 Salamanca, Spain^2

关键词: Coherence parameters;    Low carrier density;    Low temperatures;    Temperature dependence;    Transport experiments;    Universal conductance fluctuations;    Weak antilocalization;    Weak localization;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/456/1/012032/pdf
DOI  :  10.1088/1742-6596/456/1/012032

来源: IOP

【 摘 要 】

We studied weak localization (WL) and and weak antilocalization (WAL) in a eight-contacts Hall bar made of exfoliated monolayer graphene on Si-SiO2, by means of magneto-transport experiments, at temperatures between 0.3 K and 15 K. At low carrier density (n7 × 1011cm-2) we observed a transition from WL to WAL driven by the increasing of the magnetic field, while at high carrier density (n2 × 1012cm-2) only WL was observable. We analyzed the magnetic field driven WL-WAL transition and we evaluated the temperature dependence of the de-coherence parameters using an alternative method compared to previous studies. The values we obtained were corroborated by a root-mean-square analysis of the amplitude of highly-reproducible universal conductance fluctuations.