Electrically driven electron spin resonance mediated by spin–valley–orbit coupling in a silicon quantum dot

Abstract

The ability to manipulate electron spins with voltage-dependent electric fields is key to the operation of quantum spintronics devices, such as spin-based semiconductor qubits. A natural approach to electrical spin control exploits the spin-orbit coupling (SOC) inherently present in all materials. So far, this approach could not be applied to electrons in silicon, due to their extremely weak SOC. Here we report an experimental realization of electrically driven electron-spin resonance in a silicon-on-insulator (SOI) nanowire quantum dot device. The underlying driving mechanism results from an interplay between SOC and the multi-valley structure of the silicon conduction band, which is enhanced in the investigated nanowire geometry. We present a simple model capturing the essential physics and use tight-binding simulations for a more quantitative analysis. We discuss the relevance of our findings to the development of compact and scalable electron-spin qubits in silicon.

CMOS Position-Based Charge Qubits: Theoretical Analysis of Control and Entanglement

“…Figure 6 plots the electron occupancy oscillation curves in quantum dot w L (green curve) and quantum dot w R (blue curve) in the double-quantum dot structure. We used the parameters from Table 1 and expressions (19) to calculate the entries of matrix (21). Then, the set of equations (16) was solved to find the coefficients c 0 (t) and c 1 (t) and the probabilities |c 0 | 2 and |c 1 | 2 associated with the occupancy of the quantum dots.…”

“…Over recent years, there has been ongoing research on semiconductor qubits [8]- [16] due to their promising compatibility with batch fabrication and enormous progress in CMOS fabrication technologies. Inspired by previous and very recent works on charge-based semiconductor qubits [8], [10], [11], [16]- [18] and spin-based semiconductor qubits [19]- [21], here we discuss the feasibility of realizing a semiconductor charge qubit in the CMOS technology. Our proposed charge semiconductor qubit originates from a fundamental device known as a single-electron device (SED) [22]- [25].…”

“…Our research is motivated by recent, significant efforts made to advance quantum qubits and quantum gates implemented in semiconductor and, in particular, CMOS technologies, with a number of very recent studies reporting silicon quantum dots [19]- [21], [28]- [30] and support electronics [16], [31]- [37]. These studies demonstrate a more practical view on quantum computing, highlighting the feasibility of large-scale fully integrated quantum processors, where many qubits will be controlled by the means of conventional electronic circuitry.…”

Is all-electrical silicon quantum computing feasible in the long term?

“…Starting from these considerations, hybrid qubits based on three electrons in a double quantum dot provides a balanced compromise among fabrication, tunability, fast gate operations, manipulation and scalability [48]. enables much faster gate operations than using ac magnetic fields, inhomogeneous dc magnetic fields or mechanisms based on spinorbit coupling [49,50,51]. The use of oscillating magnetic or electrical fields or quasi-static Zeeman field gradient, which is mandatory in singlet-triplet qubits, is here unnecessary.…”

Electric-field control and noise protection of the flopping-mode spin qubit

“…This expression should be viewed as an approximate interpolation between the limiting cases where relaxation rate γ 1,s or the low-frequency noise are dominating [50]. Increasing the detuning localizes the electron more in a single QD and the flopping-mode EDSR mechanism described above may compete with other EDSR mechanisms that take place in a SQD, via excited orbital or valley states [23,27,[51][52][53][54][55][56]. Also in a DQD structure, if the intervalley interdot tunnel coupling [57][58][59] is strong compared to the valley splittings [59], the effective spin Rabi frequency will be modified.…”