Shot noise generated by graphene p–n junctions in the quantum Hall effect regime
نویسندگان
چکیده
Graphene offers a unique system to investigate transport of Dirac Fermions at p-n junctions. In a magnetic field, combination of quantum Hall physics and the characteristic transport across p-n junctions leads to a fractionally quantized conductance associated with the mixing of electron-like and hole-like modes and their subsequent partitioning. The mixing and partitioning suggest that a p-n junction could be used as an electronic beam splitter. Here we report the shot noise study of the mode-mixing process and demonstrate the crucial role of the p-n junction length. For short p-n junctions, the amplitude of the noise is consistent with an electronic beam-splitter behaviour, whereas, for longer p-n junctions, it is reduced by the energy relaxation. Remarkably, the relaxation length is much larger than typical size of mesoscopic devices, encouraging using graphene for electron quantum optics and quantum information processing.
منابع مشابه
Quantized Transport in Graphene p-n Junctions in a Magnetic Field.
Recent experimental work on locally gated graphene layers resulting in p-n junctions has revealed the quantum Hall effect in their transport behavior. We explain the observed conductance quantization, which is fractional in the bipolar regime and an integer in the unipolar regime, in terms of quantum Hall edge modes propagating along and across the p-n interface. In the bipolar regime, the elec...
متن کاملEdge mixing dynamics in graphene p–n junctions in the quantum Hall regime
Massless Dirac electron systems such as graphene exhibit a distinct half-integer quantum Hall effect, and in the bipolar transport regime co-propagating edge states along the p-n junction are realized. Additionally, these edge states are uniformly mixed at the junction, which makes it a unique structure to partition electrons in these edge states. Although many experimental works have addressed...
متن کاملKnitting algorithm for calculating Green functions in quantum systems
We propose a fast and versatile algorithm to calculate local and transport properties such as conductance, shot noise, local density of state, and local currents in mesoscopic quantum systems. Within the nonequilibrium Green function formalism, we generalize the recursive Green function technique to tackle multiterminal devices with arbitrary geometries. We apply our method to analyze two recen...
متن کاملConductance oscillations induced by ballistic snake states in a graphene heterojunction.
The realization of p-n junctions in graphene, combined with the gapless and chiral nature of its massless Dirac fermions has led to the observation of many intriguing phenomena such as the quantum Hall effect in the bipolar regime, Klein tunnelling and Fabry-Pérot interferences, all of which involve electronic transport across p-n junctions. Ballistic snake states propagating along the p-n junc...
متن کاملElectronic transport and quantum hall effect in bipolar graphene p-n-p junctions.
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 characterize locally gated bipolar graphene p-n-p junctions. We observe a series of fractional quantum Hall conductance plateaus at high magnetic fields as the local ...
متن کامل