An experimental study on the current shot noise of a quantum point contact with short channel length is reported. The experimentally measured maximum energy level spacing between the ground and the first excited state...An experimental study on the current shot noise of a quantum point contact with short channel length is reported. The experimentally measured maximum energy level spacing between the ground and the first excited state of the device reached up to 7.5meV, probably due to the hard wall confinement by using shallow electron gas and sharp point contact geometry. The two-dimensionM non-equilibrium shot noise contour map shows noise suppression characteristics in a wide range of bias voltage. Fano factor analysis indicates spin-polarized transport through a short quantum point contact.展开更多
Current fluctuation in electronic systems has been extensively studied due to the fact that they can pro- vide further information of charge transport compared to the conventional conductance measurements. Shot noise ...Current fluctuation in electronic systems has been extensively studied due to the fact that they can pro- vide further information of charge transport compared to the conventional conductance measurements. Shot noise is the non-equilibrium electrical fluctuation due to the discrete nature of carriers flowing through a device, reflecting correlation effects. A well-known shot noise power density as uncorrelated charge trans- mission is S - 2el, with I the average current. This Poissonian shot noise can be observed in sys- tems with a single tunnel barrier. Positive or neg- ative correlations between charged particles, induced by the Coulomb interaction and the Pauli exclusion principle, can enhance or suppress shot noise from the Poissonian value. Numerous experimental and the- oretical studies of the shot noise in mesoseopie sys- tems have been carried out on various devices such as self-assembled quantum dots, resonant tunnel- ing diodes,molecular junction devices, quan- tum point contacts,semiconductor quantum dots, and metal atomic chains. Externally driven exci- tations which affect shot noise properties were also investigated.展开更多
基金Supported by the Basic Science Research Program through the National Research Foundation of Korea under Grant No 2011-0004949
文摘An experimental study on the current shot noise of a quantum point contact with short channel length is reported. The experimentally measured maximum energy level spacing between the ground and the first excited state of the device reached up to 7.5meV, probably due to the hard wall confinement by using shallow electron gas and sharp point contact geometry. The two-dimensionM non-equilibrium shot noise contour map shows noise suppression characteristics in a wide range of bias voltage. Fano factor analysis indicates spin-polarized transport through a short quantum point contact.
文摘Current fluctuation in electronic systems has been extensively studied due to the fact that they can pro- vide further information of charge transport compared to the conventional conductance measurements. Shot noise is the non-equilibrium electrical fluctuation due to the discrete nature of carriers flowing through a device, reflecting correlation effects. A well-known shot noise power density as uncorrelated charge trans- mission is S - 2el, with I the average current. This Poissonian shot noise can be observed in sys- tems with a single tunnel barrier. Positive or neg- ative correlations between charged particles, induced by the Coulomb interaction and the Pauli exclusion principle, can enhance or suppress shot noise from the Poissonian value. Numerous experimental and the- oretical studies of the shot noise in mesoseopie sys- tems have been carried out on various devices such as self-assembled quantum dots, resonant tunnel- ing diodes,molecular junction devices, quan- tum point contacts,semiconductor quantum dots, and metal atomic chains. Externally driven exci- tations which affect shot noise properties were also investigated.
