Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userFast spin-orbit qubit in an indium antimonide nanowire
146
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Due to the strong spin-orbit interaction in indium antimonide, orbital motion and spin are no longer separated. This enables fast manipulation of qubit states by means of microwave electric fields. We report Rabi oscillation frequencies exceeding 100 MHz for spin-orbit qubits in InSb nanowires. Individual qubits can be selectively addressed due to intrinsic dierences in their g-factors. Based on Ramsey fringe measurements, we extract a coherence time T_2* = 8 +/- 1 ns at a driving frequency of 18.65 GHz. Applying a Hahn echo sequence extends this coherence time to 35 ns.
rate research
Read More
Double quantum dot in the few-electron regime is achieved using local gating in an InSb nanowire. The spectrum of two-electron eigenstates is investigated using electric dipole spin resonance. Singlet-triplet level repulsion caused by spin-orbit interaction is observed. The size and the anisotropy of singlet-triplet repulsion are used to determine the magnitude and the orientation of the spin-orbit effective field in an InSb nanowire double dot. The obtained results are confirmed using spin blockade leakage current anisotropy and transport spectroscopy of individual quantum dots.
Motion of electrons can influence their spins through a fundamental effect called spin-orbit interaction. This interaction provides a way to electrically control spins and as such lies at the foundation of spintronics. Even at the level of single electrons, spin-orbit interaction has proven promising for coherent spin rotations. Here we report a spin-orbit quantum bit implemented in an InAs nanowire, where spin-orbit interaction is so strong that spin and motion can no longer be separated. In this regime we realize fast qubit rotations and universal single qubit control using only electric fields. We enhance coherence by dynamically decoupling the qubit from the environment. Our qubits are individually addressable: they are hosted in single-electron quantum dots, each of which has a different Lande g-factor. The demonstration of a nanowire qubit opens ways to harness the advantages of nanowires for use in quantum computing. Nanowires can serve as one-dimensional templates for scalable qubit registers. Unique to nanowires is the possibility to easily vary the material even during wire growth. Such flexibility can be used to design wires with suppressed decoherence and push semiconductor qubit fidelities towards error-correction levels. Furthermore, electrical dots can be integrated with optical dots in p-n junction nanowires. The coherence times achieved here are sufficient for the conversion of an electronic qubit into a photon, the flying qubit, for long-distance quantum communication.
We study bottom-up grown semiconductor indium antimonide nanowires that are coated with shells of tin. The shells are uniform in thickness. The interface between Sn and InSb is abrupt and without interdiffusion. Devices for transport are prepared by in-situ shadowing of nanowires using nearby nanowires as well as flakes, resulting in etch-free junctions. Tin is found to induce a hard superconducting gap in the range 600-700 micro-eV. Superconductivity persists up to 4 T in magnetic field. A tin island exhibits the coveted two-electron charging effect, a hallmark of charge parity stability. The findings open avenues for superconducting and topological quantum circuits based on new superconductor-semiconductor combinations.
Spin torque from spin current applied to a nanoscale region of a ferromagnet can act as negative magnetic damping and thereby excite self-oscillations of its magnetization. In contrast, spin torque uniformly applied to the magnetization of an extended ferromagnetic film does not generate self-oscillatory magnetic dynamics but leads to reduction of the saturation magnetization. Here we report studies of the effect of spin torque on a system of intermediate dimensionality - a ferromagnetic nanowire. We observe coherent self-oscillations of magnetization in a ferromagnetic nanowire serving as the active region of a spin torque oscillator driven by spin orbit torques. Our work demonstrates that magnetization self-oscillations can be excited in a one-dimensional magnetic system and that dimensions of the active region of spin torque oscillators can be extended beyond the nanometer length scale.
We study the impacts of the magnetic field direction on the spin-manipulation and the spin-relaxation in a one-dimensional quantum dot with strong spin-orbit coupling. The energy spectrum and the corresponding eigenfunctions in the quantum dot are obtained exactly. We find that no matter how large the spin-orbit coupling is, the electric-dipole spin transition rate as a function of the magnetic field direction always has a $pi$ periodicity. However, the phonon-induced spin relaxation rate as a function of the magnetic field direction has a $pi$ periodicity only in the weak spin-orbit coupling regime, and the periodicity is prolonged to $2pi$ in the strong spin-orbit coupling regime.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
