Current oscillation of snake states in graphenep-njunction

Abstract

Snake states in a six-terminal graphene p-n junction are investigated under a perpendicular magnetic field. The current oscillation with varying magnetic field appears due to the presence of snake states at the p-n interface. At a fixed magnetic field, the periodic properties of currents with respect to the geometric structures, such as the graphene ribbon width and the location of the incident terminal, are also shown. We extract the values of the width and the location corresponding to the maximums of the current and plot them versus their sequence number. They form a straight line, which shows that the oscillation is periodic. The periods decrease with increasing magnetic field. The order of magnitude of periods and their tendencies with varying a magnetic field are consistent with those predicted from semiclassical motions. Finally, for a smooth potential, the snake states still survive and the oscillation phase and the oscillation period with respect to the location of the incident terminal are almost unchanged, but the period with respect to the width of the ribbon is reduced.

Snake trajectories in ultraclean graphene p–n junctions

“…This could be used to guide electrons away from sample edges to suppress uncontrolled momentum or spin scattering. The directional scattering at the sample boundaries could be used to implement multi-terminal switches 24 26 . Furthermore, the similarity between Andreev reflection and Klein tunnelling is stressed in theory 27 leading to a correspondence of snake states and Andreev edge states which are of theoretical 28 and experimental 29 interest.…”

Conductance oscillations induced by ballistic snake states in a graphene heterojunction

“…An increase in conductance along the p-n interface of graphene devices on SiO 2 at finite magnetic field has been observed and attributed to snake states [9]. It has been theoretically predicted that, in a higher quality device, these snake states, even though propagating along the p-n interface, can manifest themselves through oscillatory conductance across the interface as a result of alternating end points of the snake states [7,[10][11][12][13]. The high-quality p-n junction in graphene, only feasible recently following the development of graphene heterostructures [14,15], provides a perfect platform for snake states due to its gapless and chiral nature which leads to a transparent p-n junction at normal incident angle, owing to Klein tunneling [16][17][18][19].…”

Interplay between snake and quantum edge states in a graphene Hall bar with a pn-junction

“…The presence of the pn-interface in graphene allows the formation of special propagating states along it -called snake states [10][11][12][13] . Due to the Lorentz force in combination with a change of sign of the carriers on the different sides of the pn-junction causes the bending of the current towards the pn-interface resulting in a channel of high mobility carriers along the pn-junction.…”