Full shot noise in mesoscopic tunnel barriers

Enhanced shot noise in asymmetric interacting two-level systems

“…Examples of such systems are quantum dots that are coupled to ferromagnetic leads [7][8][9][10] , multi-levels quantum dots 11,12 , multidots structures [13][14][15][16][17][18] , and also three terminal quantum dots [19][20][21] . There are also experimental works [22][23][24][25][26] in which a super-Poisson noise was measured in quantum dots, rather than the sub-Poisson noise, which is expected from the single level model of the quantum dots.…”

Positive Current Correlations Associated with Super-Poissonian Shot Noise

“…After tunneling through the barrier, they are incident on the beam splitter, where partition occurs and the electrons are scattered into two channels C and D. The current fluctuations in both channels are measured by two cryogenic amplifiers, and are further amplified at room temperature and eventually fed into a spectrum analyzer, which calculates the cross spectrum. All measurements are done in a 20 kHz window around 220 kHz and at a temperature of 70 mK [16].…”

“…(1) to Eq. (2) is straightforward for ideal tunnel barriers, we want to point out that most barriers fabricated in a 2DEG in GaAs=AlGaAs heterostructures are nonideal [17,18], especially in the pinch-off regime (T 1) [16]. In these barriers, the relation between F and T can be very complicated and extremely sensitive to microscopic details such as the spatial and energy distribution of localized states.…”

“…In our setup, shot noise signal is loaded to a resistor and measured as voltage fluctuations across it [16]. A circuit model that relates such fluctuations to the shot noise signal is then used to extract F [22].…”

Current Fluctuations in Single Barrier Vertical GaAs/AlAs/GaAs Tunneling Devices

“…the existence and number of localized states which participate in the transport) [1]. The single-barrier resonant-tunneling device is interesting for its simplicity and many authors had investigated electronic transport in this system until now [2,3]. Incorporating impurities inside the barriers change dramatically its properties, enable resonant transport through the barrier and make it useful for applications.…”