Spatial mobility fluctuation induced giant linear magnetoresistance in multilayered graphene foam
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
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AbstractGiant, positive, and near-temperature-independent linear magnetoresistance (LMR), as large as 340%, was observed in graphene foam with a three-dimensional flexible network. Careful analysis of the magnetoresistance revealed that Shubnikov–de Haas (SdH) oscillations occurred at low temperatures and decayed with increasing temperature. The average classical mobility ranged from 300 (2 K) to 150 (300 K) cm2V−1s−1, which is much smaller than that required by the observed SdH oscillations. To understand the mechanism behind the observation, we performed the same measurements on the microsized graphene sheets that constitute the graphene foam. Much more pronounced SdH oscillations superimposed on the LMR background were observed in these microscaled samples, which correspond to a quantum mobility as high as 26,500cm2V−1s−1. Moreover, the spatial mobility fluctuated significantly from 64,200cm2V−1s−1 to 1370cm2V−1s−1, accompanied by a variation of magnetoresistance from near 20,000% to less than 20%. The presence of SdH oscillations actually excludes the possibility that the observed LMR originated from the extreme quantum limit, because this would demand all electrons to be in the first Landau level. Instead, we ascribe the large LMR to the second case of the classical Parish and Littlewood model, in which spatial mobility fluctuation dominates electrical transport. This is an experimental confirmation of the Parish and Littlewood model by measuring the local mobility randomly (by measuring the microsized graphene sheets) and finding the spatial mobility fluctuation.
CitationSpatial mobility fluctuation induced giant linear magnetoresistance in multilayered graphene foam 2016, 94 (4) Physical Review B
SponsorsP.L. was supported by a Saudi Basic Industries Corporation (SABIC) Postdoctoral Fellowship Award in the Kingdom of Saudi Arabia. H.-M.C. and W.R. acknowledge the financial support by the National Natural Science Foundation of China (Grant No. 51221264), the Ministry of Science and Technology of China (Grant No. 2012AA030303), and the Chinese Academy of Sciences (Grants No. KGZD-EW-303-1 and No. KGZD-EW-T06). We are grateful to Jun Li and Zhiyong Zhu for helpful discussions. This work was mainly supported by the King Abdullah University of Science and Technology.
PublisherAmerican Physical Society (APS)
JournalPhysical Review B