相关论文: Quantized coexisting electrons and holes in graphe…
Hole-conjugate states of the fractional quantum Hall effect host counter-propagating edge channels which are thought to exchange charge and energy. These exchanges have been the subject of extensive theoretical and experimental works; in…
From the scattering of semicoherent-state wavepackets at high magnetic field, we derive analytically the transmission coefficient of electrons in graphene in the quantum Hall regime through a smooth constriction described by a quadratic…
We studied the magneto-transport in SiO2 substrate-supported monolayer graphene and the quantum phase transitions that characterize the quantum Hall regime, using magnetic fields up to 28T and temperatures down to 4K. The analysis of the…
We investigate carrier transport in a single 22 nm-thick double-gated Si quantum well device, which has independent contacts to electrons and holes. Conductance, Hall density and Hall mobility are mapped in a broad double-gate voltage…
We theoretically study the transport properties of both monolayer and bilayer graphene in the presence of electron-hole puddles induced by charged impurities which are invariably present in the graphene environment. We calculate the…
Materials subjected to a magnetic field exhibit the Hall effect, a phenomenon studied and understood in fine detail. Here we report a qualitative breach of this classical behavior in electron systems with high viscosity. The viscous fluid…
The wave nature of electrons in low-dimensional structures manifests itself in conventional electrical measurements as a quantum correction to the classical conductance. This correction comes from the interference of scattered electrons…
It is widely believed that carrier-density inhomogeneities ("electron-hole puddles") in single-layer graphene on a substrate like quartz are due to charged impurities located close to the graphene sheet. Here we demonstrate by using a…
The Hall effect, and the diagonal resistance, which indicates a residual resistivity $\rho_{xx} \approx h/4e^{2}$, are experimentally examined over the p$\leftrightarrow$n transition about the nominal neutrality point in chemical vapor…
Coulomb drag between adjacent electron and hole gases has attracted considerable attention, being studied in various two-dimensional systems, including semiconductor and graphene heterostructures. Here we report measurements of…
The quantum Hall (QH) effect in two-dimensional electron systems (2DESs) is conventionally observed at liquid-helium temperatures, where lattice vibrations are strongly suppressed and bulk carrier scattering is dominated by disorder.…
The conductivity and Hall effect were measured in CVD-grown monolayer graphene as a function of the gate voltage, $V_{g}$, at temperatures down to $T$ = 2 K and in magnetic fields up to $B$ = 8 T. The minimal conductivity was observed at…
We report observation of the fractional quantum Hall effect (FQHE) in high mobility multi-terminal graphene devices, fabricated on a single crystal boron nitride substrate. We observe an unexpected hierarchy in the emergent FQHE states that…
We have measured the temperature and magnetic field dependence of the Hall coefficient ($R_{\rm H}$) in three, several micrometer long multigraphene samples of thickness between $\sim 9~$to $\sim 30$~nm in the temperature range 0.1 to 200~K…
Collisions between electrons and holes can dominate the carrier scattering in clean graphene samples in the vicinity of charge neutrality point. While electron-hole limited resistance in pristine gapless graphene is well-studied, its…
Vertical heterostructures combining different layered materials offer novel opportunities for applications and fundamental studies of collective behavior driven by inter-layer Coulomb coupling. Here we report heterostructures comprising a…
Unconventional magneto-transport fingerprints in the quantum Hall regime (with applied magnetic field from one to several tens of Tesla) in chemically functionalized graphene are reported. Upon chemical adsorption of monoatomic oxygen (from…
We have developed a device fabrication process to pattern graphene into nanostructures of arbitrary shape and control their electronic properties using local electrostatic gates. Electronic transport measurements have been used to…
We report an observation of conductance fuctuations (CFs) in the bipolar regime of quantum hall (QH) plateaus in graphene (p-n-p/n-p-n) devices. The CFs in the bipolar regime are shown to decrease with increasing bias and temperature. At…
We investigate bilayer graphene transport in the presence of electron-hole puddles induced by long-range charged impurities in the environment. We explain the insulating behavior observed in the temperature dependent conductivity of low…