Transport properties of monolayer and bilayer graphene p–n junctions with charge puddles in the quantum Hall regime

Abstract

Recent experiments have confirmed that the electron-hole inhomogeneity in graphene is a new type of charge disorder. Motivated by such confirmation, we theoretically study the transport properties of a monolayer graphene (MLG) based p-n junction and a bilayer graphene (BLG) p-n junction in the quantum Hall regime where electron-hole puddles are considered. By using the non-equilibrium Green function method, both the current and conductance are obtained. We find that, in the presence of the electron-hole inhomogeneity, the lowest quantized conductance plateau at e(2)/h emerges in the MLG p-n junction under very small charge puddle disorder strength. For a BLG p-n junction, however, the conductance in the p-n region is enhanced with charge puddles, and the lowest quantized conductance plateau emerges at 2e(2)/h. Besides, when an ideal quantized conductance plateau is formed for a MLG p-n junction, the universal conductance fluctuation is found to be 2e(2)/3h. Furthermore, we also investigate the influence of Anderson disorder on such p-n junctions and the comparison and discussion are given accordingly. To compare the two models with different types of disorder, we investigate the conductance distribution specially. Finally the influence of disorder strength on the conductance of a MLG p-n junction is investigated.

Chirality effect in disordered graphene ribbon junctions

“…h, which can be ascribed to mode mixing, induced by disorder, between parallel-traveling edge states along the junction interface [43][44][45][46][47][48]. These results were also confirmed by other subsequent experiments [49][50][51].…”

Dephasing effect on transport of a graphene p–n junction in a quantum Hall regime

“…Thus, the dual-gated device enabled by graphene nanoribbons is realized. Such devices, like p-n and p-n-p junctions, were extensively investigated in the past few years both experimentally [3][4][5] and theoretically [6][7][8][9][10][11][12] for the transport properties [3][4][5][6][7][8][9][10] and exotic phenomena, for instance, relativistic Klein tunneling [11] and Veselago lensing [12].…”

Gate tunable non-linear currents in bilayer graphene diodes

“…They are caused by variable range hopping (and by nearest neighbor hopping especially in the lower temperature region than variable range hopping 12 ) and by thermally activated transport over the bandgap, respectively. The formation of bilayer graphene pn junctions has attracted considerable theoretical interest [15][16][17] and it is a key element in graphene-based electronics. Though up to date there is only one experimental report on pn-junction devices, no evidence for a rectified current has yet been reported leaving graphene-based electronics still a pure academic exercise 18 .…”