Shot noise of coupled semiconductor quantum dots

Enhanced shot noise in tunneling through a stack of coupled quantum dots.

We have investigated the noise properties of the tunneling current through vertically coupled self-assembled InAs quantum dots. We observe super-Poissonian shot noise at low temperatures. For increased temperature this effect is suppressed. The super-Poissonian noise is explained by capacitive coupling between different stacks of quantum dots.

Cotunneling current and shot noise in quantum dots.

We derive general expressions for the current and the shot noise, taking into account non-Markovian memory effects. In generalization of previous approaches, our theory is valid for an arbitrary Coulomb interaction and coupling strength and is applicable to quantum dots and more complex systems such as molecules. A fully consistent diagrammatic expansion up to second order in the coupling stren...

Coherent manipulation of coupled electron spins in semiconductor quantum dots.

We demonstrated coherent control of a quantum two-level system based on two-electron spin states in a double quantum dot, allowing state preparation, coherent manipulation, and projective readout. These techniques are based on rapid electrical control of the exchange interaction. Separating and later recombining a singlet spin state provided a measurement of the spin dephasing time, T2*, of app...

Asymmetric exchange between electron spins in coupled semiconductor quantum dots

Semiconductor Quantum Dots

The “Standard Model” of the Electronic Structure of Dots Progress made in the growth of “freestanding” (e.g., colloidal) quantum dotslt2 (see also articles in this issue by Nozik and MiCi6, and by Alivisatos) and in the growth of semiconductor-embedded (“self-assembled”) dots3p4 (see also the article by Bimberg, Grundmann, and Ledentsov in this issue) has opened the door to new and exciting spe...