Interdot coupling in a Si-based coupled double dot system for spin qubit gate

Abstract

A Si-based coupled double dot has been studied for its application to two-qubit gate. The authors manipulated electron number of each dot by using its adjacent side gate and finally observed a honeycomb charge-stability pattern, demonstrating interdot capacitive coupling. From the honeycomb diagram the capacitance-related interdot coupling parameters were extracted. Moreover, a fine structure in a conductance trace near the triple point of the honeycomb, where the tunnel coupling is maximized, was measured for finite bias, and its dependence on the interdot coupling was attributed to the spin exchange between the two dots.

Singlet-triplet relaxation in SiGe/Si/SiGe double quantum dots

“…[1][2][3][4] Recently, silicon QDs have attracted much attention due to their outstanding spin-related properties. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Specifically, the hyperfine interaction can be reduced by isotopic purification. 25 The Dresselhaus spinorbit coupling (SOC) 26 is absent thanks to the bulk-inversion symmetry, and the SOC induced by the interface-inversion asymmetry (IIA) is rather weak.…”

“…30,31 Nowadays, spin qubits in silicon single and double QDs have been actively investigated. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] In silicon single QDs, we have studied the singlet-triplet (ST) relaxation by explicitly including the electron-electron Coulomb interaction and the multivalley effect. Our results in the Voigt configuration agree quite well with the recent experiment by Xiao et al 16 Silicon double QDs, which have been proven very useful in exploiting the spin Coulomb blockade, 32 have also attracted much attention.…”

Electrostatically defined few-electron double quantum dot in silicon

“…This should, in principle, increase the coherence time of electron-spin qubits in silicon [7,8]. Initial demonstrations of Si-based DQD systems for spin qubits [9,10] have stimulated a number of recent studies of DQDs in both multi-gated silicon-on-insulator (SOI) [11,12] and Si/SiGe [13] structures.…”