Measuring the coherence of charge states in undoped GaAs/AlGaAs double quantum dots with photon-assisted tunneling
1 Key Laboratory of Quantum Information, Chinese Academy of Sciences, University of Science and Technology of China - Hefei, Anhui 230026, China and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China - Hefei, Anhui 230026, China
Received: 21 April 2015
Accepted: 21 June 2015
Photon-assisted tunneling is used to study coherent properties of a charge qubit which is formed in an undoped GaAs/AlGaAs heterostructure. We found the charge relaxation time T1 to be around 15 ns and the inhomogeneous decoherence time to be around 330 ps at an electron temperature of 280 mK. This may be slightly better than that previously reported for doped devices, considering its temperature dependence. We discuss the role of donor fluctuation on the charge state coherence and possible ways for making improvements in the undoped devices.
PACS: 73.21.La – Quantum dots
© EPLA, 2015