Large tunable linear magnetoresistance in gold nanoparticle decorated graphene

Abstract

Addendum: "Large room-temperature quantum linear magnetoresistance in multilayered epitaxial graphene: Evidence for two-dimensional magnetotransport" [Appl.We propose and demonstrate gold nanoparticle decorated graphene as an ideal system for studying carrier inhomogeneity induced magnetoresistance. Large linear magnetoresistance has been realized in the system and the magnitude can be tuned by a gate. By detailed study, we provide an empirical expression, which reveals the dependence of the magnetoresistance on density fluctuations and mobility. The induced magnetoresistance is temperature independent and can be strongly enhanced by the high mobility of graphene, hence offers potential for magnetic sensor applications. V C 2014 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4897277]Graphene, being only one atom thick, represents a perfect two dimensional electron gas (2DEG) material. Unlike most of conventional 2DEG systems, e.g., semiconductor heterostructures, where electron gas is buried in bulk materials, graphene is completely exposed to environment. This provides direct access to its electron gas. For instance, the surface morphology can be imaged in atomic resolution, while the charge carrier distribution can be mapped out at the same time. 1 The band structure can also be engineered by simple surface functionalization. 2 Recently, there has been increasing interest in using absorption of metal adatoms to modify the interactions between different degrees of freedom in graphene, such as the spin-orbit interaction 3-6 and electron-phonon interaction. 7-9 As predicted by theories, some salient condensed matter phenomena, such as topological insulators, 3,5,10 ferromagnetic order, 11,12 and superconductivity 7,9 can be realized in graphene by this means. Experimental confirmation of the predictions will offer a unique opportunity to study these phenomena, owing to the great tunability of graphene. Such an advantage has been nicely demonstrated in a recent experiment, 13,14 where the superconducting transition of a graphene/superconductor islands hybrid has been studied. In that system, the coupling between superconducting islands can be conveniently tuned via carrier density in graphene by a back gate.In this work, we propose to use graphene to study the linear magnetoresistance (LMR) induced by carrier inhomogeneity. LMR has attracted lots of attention, partially due to its application in magnetic field sensors. It has been seen in various systems, for instance, Bismuth, 15 graphite, 16 Indium antimonide, 17 LaSb 2 , 18 InAs, 19 multilayer epitaxial graphene, 20 and Bi 2 Te 3 . 10,21 However, the mechanism can be very different. It is well known that the specific topology of the Fermi surface, i.e., an open orbit, can lead to LMR. 22 Beside this classical effect, when the carrier is of low density and small effective mass, the quantum limit, in which all carriers lie in the lowest Landau level, can be reached. It has been proposed that LMR can arise in such condition, called quantum LMR. 16,23 In the pas...

Current Progress of Magnetoresistance Sensors

“…Graphene foams (GF) are three-dimensional arranged graphene structures with good biocompatibility and MR property [36][37][38][39][40][41][42]. Hybrid graphene nanocomposites with MR are constructed with graphene and reduced graphene oxide (rGO) [29,[43][44][45][46][47][48][49][50].…”

“…Two different routes are adopted to achieve large MR values for hybrid graphene nanocomposites. In the first route, nanoparticles/adatoms clusters are decorated on the surface of CVD/mechanical exfoliation prepared graphene layers by thermal evaporation or electron beam deposition [43][44][45][46][47]. Both positive and negative MR were obtained in this route.…”

“…Based on CVD/mechanical exfoliation produced graphene Relatively large values were achieved for both positive and negative MR Future applications in fabricating graphene-based circuits Special designed substrate/circuits are required for CVD/mechanical exfoliation produced graphene leads to complicated fabrication processes with more investments and time costs Exhibiting small magnitude of MR at room temperature [43][44][45][46][47] Based on reduced graphene oxide (rGO) rGO and rGO hybrid nanocomposites can be both obtained with facile preparation processes leads to lesser requirements on special equipment Reduced investments in instruments and simplified production process (cost-effective and friendly for mass production) Large MR was achieved by the rGO hybrid nanocomposites Current results of rGO hybrid nanocomposites show relatively small MR at the low magnetic field (<10 kOe) and room temperature Few investigations have been performed to develop and improve the MR of rGO hybrid nanocomposites [29,[48][49][50]…”

Rashba Interaction and Local Magnetic Moments in a Graphene-BN Heterostructure Intercalated with Au

“…However, Au in a nanoparticle configuration [11] induces n-doping +5 × 10 11 cm −2 attributed to the reduced Au-graphene separation and lower effective potential. Clustered Au produces local variations in the Fermi level and scattering leading to positive linear MR [12] and an extrinsic spin Hall effect [13,14].…”

“…Graphene on SiC intercalated with Au shows large shifts in doping (> 10 attributed to the reduced Au-graphene separation and lower effective potential. Clustered Au produces local variations in the Fermi level and scattering leading to positive linear MR [12] and an extrinsic spin Hall effect [13,14].Au is always present in the samples presented here, but as fabricated samples show longitudinal (ρ xx ) and Hall (ρ xy ) resistivity characteristic of pristine graphene, shown in Fig. 1d for 0.1 ML Au and field effect mobility 1.2 × 10 5 cm 2 /Vs; however, the MR is negative (supplementary information).…”