**Toward Quantum Information Processing Devices with Semiconductor and Graphene Quantum Dots ** - Pawel Hawrylak

We describe progress in theory and experiments on semiconductor and graphene quantum dots with potential applications in nanoelectronics, nanospintronics, nanophotonics and quantum information processing. The lateral quantum dots defined using metallic gates in GaAs/GaAlAs field effect transistor are one of the most advanced artificial quantum systems in solid state. We will describe a stability diagram and spin blockade in triple quantum dot molecule with controlled electron numbers in each dot[1], discuss potential use of such a molecule in entanglement and Berry�s phase generation[2], chirality based qubits[3] and as building block of a FET with a macroscopic quantum groundstate[4]. We next turn to hybrid systems of self-assembled semiconductor CdTe quantum dots containing single magnetic impurities. Such impurities can be thought of as an atomic limit of quantum memory directly integrated into a semiconductor host. We show that the optical detection and manipulation of impurity spins is governed by the quantum interference between the electron, hole and impurity spin[5,6]. Finally, we discuss one atom thick semiconductor quantum dots made of graphene[7-10], hence potentially free of nuclear spins. We show that their electronic, optical and magnetic properties can be engineered by the size, shape, type of edge and number of layers[7-10]. We focus on their optical and magnetic properties, and their control with external gate, electric field and photons. Possibility of realizing a fully integrated carbon-only quantum circuit will be discussed.
References:
Chang-Yu Hsieh, Yun-Pil Shim, and Pawel Hawrylak,Phys. Rev. B 85, 085309 (2012).
Anand Sharma and Pawel Hawrylak , Phys. Rev. B 83, 125311 (2011).
Chang-Yu Hsieh and P.Hawrylak, Phys.Rev.B 82,205311(2010).
Yun-Pil Shim, Anand Sharma, Chang-Yu Hsieh, Pawel Hawrylak, Solid State Comm. 150, 2065(2010).