scholarly journals Weak localization correction to the density of transmission eigenvalues in the presence of magnetic field and spin-orbit coupling for a chaotic quantum dot

2006 ◽  
Vol 74 (23) ◽  
Author(s):  
Benjámin Béri ◽  
József Cserti
Keyword(s):  
Magnetic Field ◽  
Quantum Dot ◽  
Weak Localization ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Transmission Eigenvalues

scholarly journals Controlling Synthetic Spin-Orbit Coupling in a Silicon Quantum Dot with Magnetic Field

2021 ◽  
Vol 15 (4) ◽  
Author(s):  
Xin Zhang ◽  
Yuan Zhou ◽  
Rui-Zi Hu ◽  
Rong-Long Ma ◽  
Ming Ni ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Dot ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Silicon Quantum Dot

scholarly journals Spin manipulation and decoherence in a quantum dot mediated by a synthetic spin-orbit coupling of broken $T$-symmetry

2021 ◽  
Author(s):  
Peihao Huang ◽  
Xuedong Hu
Keyword(s):  
Magnetic Field ◽  
Quantum Dot ◽  
Spin Relaxation ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Field Orientation ◽  
Spin Manipulation ◽  
Pure Dephasing ◽  
Spin Qubit

Abstract The electrical control of a spin qubit in a quantum dot relies on spin-orbit coupling (SOC), which could be either intrinsic to the underlying crystal lattice or heterostructure, or extrinsic via, for example, a micro-magnet. In experiments, micromagnets have been used as a synthetic SOC to enable strong coupling of a spin qubit in quantum dots with electric fields. Here we study theoretically the spin relaxation, pure dephasing, spin manipulation, and spin-photon coupling of an electron in a quantum dot due to the synthetic SOC induced spin-orbit mixing. We find qualitative difference in the spin dynamics in the presence of a synthetic SOC compared with the case of the intrinsic SOC. Specifically, spin relaxation due to the synthetic SOC and deformation potential phonon emission (or Johnson noise) shows $B_0^5$ (or $B_0$) dependence with the magnetic field, which is in contrast with the $B_0^7$ (or $B_0^3$) dependence in the case of the intrinsic SOC. Moreover, charge noise induces fast spin dephasing to the first order of the synthetic SOC, which is in sharp contrast with the negligible spin pure dephasing in the case of the intrinsic SOC. These qualitative differences are attributed to the broken time-reversal symmetry ($T$-symmetry) of the synthetic SOC. An SOC with broken $T$-symmetry (such as the synthetic SOC from a micro-magnet) eliminates the ``Van Vleck cancellation'' and causes a finite longitudinal spin-electric coupling that allows the longitudinal coupling between spin and electric field, and in turn allows spin pure dephasing. Finally, through proper choice of magnetic field orientation, the electric-dipole spin resonance via the synthetic SOC can be improved with potential applications in spin-based quantum computing.

scholarly journals Observation of spin–orbit coupling induced Weyl points in a two-electron double quantum dot

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Zoltán Scherübl ◽  
András Pályi ◽  
György Frank ◽  
István Endre Lukács ◽  
Gergő Fülöp ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Dot ◽  
Kondo Effect ◽  
Surface States ◽  
Orbit Coupling ◽  
Double Quantum ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Electronic Band ◽  
Ground State Degeneracy

Abstract Recent years have brought an explosion of activities in the research of topological aspects of condensed-matter systems. Topological phases of matter are accompanied by protected surface states or exotic degenerate excitations such as Majorana modes or Haldane’s localized spinons. Topologically protected degeneracies can, however, also appear in the bulk. An intriguing example is provided by Weyl semimetals, where topologically protected electronic band degeneracies and exotic surface states emerge even in the absence of interactions. Here we demonstrate experimentally and theoretically that Weyl degeneracies appear naturally in an interacting quantum dot system, for specific values of the external magnetic field. These magnetic Weyl points are robust against spin–orbit coupling unavoidably present in most quantum dot devices. Our transport experiments through an InAs double-dot device placed in magnetic field reveal the presence of a pair of Weyl points, exhibiting a robust ground-state degeneracy and a corresponding protected Kondo effect.

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