Tunable Noise CrossCorrelations
in a Double Quantum Dot
C.M. Marcus
a) Electron micrograph of parallel double quantum dot. The
dots are tuned into the Coulomb blockade regime with purely capacitive interdot
coupling (the central point contact is pinched off, preventing interdot
tunneling). The schematic shows the detection system measuring the
auto and crosscorrelation of fluctuations, or noise, in currents It and
Ib through top and bottom quantum dots. (b) Zerobias differential conductances
gt and gb as a function of plunger gate voltages Vbc and Vtc. Dark
regions correspond to fixed electron number (M, N) in the double dot. The
superimposed white lines indicate the honeycomb structure that results from
interdot capacitive coupling. (c) Measured noise crosscorrelation
at fixed bias VT=VB=100 mV in the vicinity of the central honeycomb vertex
in (b). The sign of the noise crosscorrelation is tunable by gate voltage.
(d) A master equation simulation of sequential tunneling with interdot
capacitive coupling reproduces the characteristic quadrupole pattern
of positive and negative crosscorrelation that is observed experimentally.
From “Tunable Noise CrossCorrelations in a Double Quantum Dot” by D.T.
McClure, L. DiCarlo, Y. Zhang, H.A. Engel, C.M. Marcus, M.P.
Hanson, and A.C. Gossard (submitted to Physical Review
Letters, condmat/0607280).
