VietNam 2013 

IXth Rencontres du Vietnam
Quy-Nhon, August 4-10, 2013

 QNplage

 Nanophysics: from fundamentals to applications

(the return)

 

Tuesday 6
Poster Session

› 21:00 - 23:00 (2h)
Shot noise measurement at the quantum point contact on two-dimensional hole gas
Yoshitaka Nishihara  1, 2@  , Kensaku Chida  2, 1@  , Tomonori Arakawa  1, 2@  , Sadashige Matsuo  1, 2@  , Takahiro Tanaka  1, 2@  , Kensuke Kobayashi  2@  , Teruo Ono  1@  , Yashar Komijani  3@  , Thomas Ihn  3@  , Klaus Ensslin  3@  , Dirk Reuter  4@  , Andreas Wieck  4@  
1 : Institute for Chemical Research, Kyoto University
Uji, Kyoto 611-0011 -  Japan
2 : Graduate School of Science, Osaka University
1-1 Machikaneyama, Toyonaka, Osaka 560-0043 -  Japan
3 : Solid State Physics Laboratory, ETH Zürich
8093 Zurich -  Switzerland
4 : Angewandte Festkörperphysik, Ruhr-Universität Bochum
44780 Bochum -  Germany

Shot noise is a powerful probe to address details of the fundamental transport properties, such as quantum statistics, scattering, and many-body effects. The shot noise measurement at a quantum point contact (QPC) fabricated on two-dimensional electron gas have been performed already by many researchers. Compared to such conventional QPCs, it is very interesting to investigate the hole QPC which have larger effective mass and stronger spin-orbit interaction than electrons.

Here we present the shot noise measurement at the QPC on two-dimensional hale gas. The conductance and the shot noise were measured at the QPC fabricated on p-doped GaAs/AlGaAs heterostructure.

The QPC shows the clear quantized plateau at 2e^2/h via adjusting a side gate bias voltage below 1 K. In addition, we can see the extra plateau at 0.7(2e^2/h), so called 0.7 structures, which remains visible above 1 K. The Fano factor calculated from the shot noise measured in 1.5 K is observed to be close to zero at quantized conductance plateau, whose behavior is similar to that of the electron QPC. However, the shot noise measured in 0.6 and 0.3 K around the 0.7 structure unexpectedly exhibits a peak structure around zero bias, which is reminiscent of the zero-bias conductance anomaly. 


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