Electrical control of the hole spin qubit in Si and Ge nanowire quantum dots

Abstract

Strong, direct Rashba spin-orbit coupling in Si, Ge, and the Ge/Si core/shell nanowire quantum dot (QD) allows for all electrical manipulation of the hole spin qubit. Motivated by this fact, we analyze different fabrication-dependent properties of nanowires, such as orientation, cross section, and the presence of strain, with the goal being to find the material and geometry that enables the fastest qubit manipulation, whose speed can be identified using the Rabi frequency. We show that QD in nanowires with a circular cross section (cNWs) enables much weaker driving of the hole spin qubit than QDs embedded in square profile nanowires (sNWs). Assuming the orientation of the Si nanowire that maximizes the spin-orbit effects, our calculations predict that the Rabi frequencies of the hole spin qubits inside Ge and Si sNW QD have comparable strengths for weak electric fields. The global maximum of the Rabi frequency is found in Si sNW QD for strong electric fields, putting this setup ahead of others in creating the hole spin qubit. Finally, we demonstrate that strain in the Si/Ge core/shell nanowire QD decreases the Rabi frequency. In cNW QD, this effect is weak; in sNW QD, it is possible to optimize the impact of strain with the appropriate tuning of the electric field strength.

11 pages, 7 figures

References in corpus (12)

• Driven coherent oscillations of a single electron spin in a quantum dot
• Coherent control of a single electron spin with electric fields
• An addressable quantum dot qubit with fault-tolerant control fidelity
• Strong and Tunable Spin-Orbit Coupling of One-Dimensional Holes in Ge/Si Core/Shell Nanowires
• Heavy hole states in Germanium hut wires
• Squeezed hole spin qubits in Ge quantum dots with ultrafast gates at low power
• Strong spin-orbit interaction and $g$-factor renormalization of hole spins in Ge/Si nanowire quantum dots
• Spin dynamics in a strongly driven system: very slow Rabi oscillations
• Tunable g factor and phonon-mediated hole spin relaxation in Ge/Si nanowire quantum dots
• Simple model for electrical hole spin manipulation in semiconductor quantum dots: Impact of dot material and orientation
• Acoustic phonons and strain in core/shell nanowires
• Electric dipole spin resonance at shallow donors in quantum wires

Cited by in corpus (13)

• Hole Spin Qubits in Ge Nanowire Quantum Dots: Interplay of Orbital Magnetic Field, Strain, and Growth Direction
• Ultrafast and Electrically Tunable Rabi Frequency in a Germanium Hut Wire Hole Spin Qubit
• Enhanced orbital magnetic field effects in Ge hole nanowires
• Majorana zero modes in gate-defined germanium hole nanowires
• Electrical operation of hole spin qubits in planar MOS silicon quantum dots
• Germanium-based hybrid semiconductor-superconductor topological quantum computing platforms: Disorder effects
• Proximity-enabled control of spin-orbit coupling in phosphorene symmetrically and asymmetrically encapsulated by WSe${}_2$ monolayers
• Two-band description of the strong `spin'-orbit coupled one-dimensional hole gas in a cylindrical Ge nanowire
• Electrical manipulation of a hole `spin'-orbit qubit in nanowire quantum dot: the nontrivial magnetic field effects
• Cancelling second order frequency shifts in Ge hole spin qubits via bichromatic control
• Hole subband dispersions and strong `spin'-orbit coupling in a cylindrical Ge nanowire
• Spin-photon interaction in a nanowire quantum dot with asymmetrical confining potential
• Giant Rabi frequencies between qubit and excited hole states in silicon quantum dots