Edge 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 this issue, the microscopic dynamics of electron partition in this peculiar structure remains unclear. Here we performed shot-noise measurements on the junction in the quantum Hall regime as well as at zero magnetic field. We found that, in sharp contrast with the zero-field case, the shot noise in the quantum Hall regime is finite in the bipolar regime, but is strongly suppressed in the unipolar regime. Our observation is consistent with the theoretical prediction and gives microscopic evidence that the edge states are uniquely mixed along the p-n junction.
Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan.|Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Sadashige
S
Matsuo
Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan.
Shunpei
S
Takeshita
Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan.
Takahiro
T
Tanaka
WPI-MANA, NIMS, Tsukuba, Ibaraki 305-0044, Japan.
Shu
S
Nakaharai
WPI-MANA, NIMS, Tsukuba, Ibaraki 305-0044, Japan.
Kazuhito
K
Tsukagoshi
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Takahiro
T
Moriyama
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Teruo
T
Ono
Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan.
Kensuke
K
Kobayashi