Tunable<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>φ</mml:mi></mml:math>Josephson junction ratchet

Menditto, R.; Sickinger, H.; Weides, Martin; Kohlstedt, H.; Koelle, D.; Kleiner, R.; Goldobin, E.

doi:10.1103/physreve.94.042202

Cited by 15 publications

(5 citation statements)

References 46 publications

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“…It is interesting to see that similar magnetic field-induced symmetry breaking exists widely in nature, such as the magnetic field-induced asymmetric Josephson energy for a Josephson ratchet composed by a φ Josephson junction and a ferromagnetic barrier 31 . Additionally, besides the Thiele equations used in this paper, the current-driven motion of domain wall can also be investigated by some other methods.…”

Section: Discussionmentioning

confidence: 98%

Spin-orbit-torque-induced magnetic domain wall motion in Ta/CoFe nanowires with sloped perpendicular magnetic anisotropy

Zhang

Luo

Yang

et al. 2017

Sci Rep

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In materials with the gradient of magnetic anisotropy, spin-orbit-torque-induced magnetization behaviour has attracted attention because of its intriguing scientific principle and potential application. Most of the magnetization behaviours microscopically originate from magnetic domain wall motion, which can be precisely depicted using the standard cooperative coordinate method (CCM). However, the domain wall motion in materials with the gradient of magnetic anisotropy using the CCM remains lack of investigation. In this paper, by adopting CCM, we established a set of equations to quantitatively depict the spin-orbit-torque-induced motion of domain walls in a Ta/CoFe nanotrack with weak Dzyaloshinskii–Moriya interaction and magnetic anisotropy gradient. The equations were solved numerically, and the solutions are similar to those of a micromagnetic simulation. The results indicate that the enhanced anisotropy along the track acts as a barrier to inhibit the motion of the domain wall. In contrast, the domain wall can be pushed to move in a direction with reduced anisotropy, with the velocity being accelerated by more than twice compared with that for the constant anisotropy case. This substantial velocity manipulation by anisotropy engineering is important in designing novel magnetic information devices with high reading speeds.

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Section: Discussionmentioning

confidence: 98%

Spin-orbit-torque-induced magnetic domain wall motion in Ta/CoFe nanowires with sloped perpendicular magnetic anisotropy

Zhang

Luo

Yang

et al. 2017

Sci Rep

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“…Experimentally, the quantum ratchet effects in semiconductor heterostructure with artificial asymmetric gating [22], Josephson junction array [23], and ϕ Josephson junction [24] are reported.…”

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confidence: 99%

Scaling theory of a quantum ratchet

et al. 2019

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The asymmetric responses of the system between the external force of right and left directions are called "nonreciprocal". There are many examples of nonreciprocal responses such as the rectification by p-n junction. However, the quantum mechanical wave does not distinguish between the right and left directions as long as the time-reversal symmetry is intact, and it is a highly nontrivial issue how the nonreciprocal nature originates in quantum systems. Here we demonstrate by the quantum ratchet model, i.e., a quantum particle in an asymmetric periodic potential, that the dissipation characterized by a dimensionless coupling constant α plays an essential role for nonlinear nonreciprocal response. The temperature (T ) dependence of the second order nonlinear mobility µ2 is found to be µ2 ∼ T 6/α−4 for α < 1, and µ2 ∼ T 2(α−1) for α > 1, respectively, where αc = 1 is the critical point of the localization-delocalization transition, i.e., Schmid transition. On the other hand, µ2 shows the behavior µ2 ∼ T −11/4 in the high temperature limit. Therefore, µ2 shows the nonmonotonous temperature dependence corresponding to the classical-quantum crossover. The generic scaling form of the velocity v as a function of the external field F and temperature T is also discussed. These findings are relevant to the heavy atoms in metals, resistive superconductors with vortices and Josephson junction system, and will pave a way to control the nonreciprocal responses.

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“…It was rigorously framed into mathematical mechanics by V. I. Arnold [19] and is known as an Arnold problem in nonlinear dynamics [20][21][22]. The indeterministic nature of the branching on damping in the phase Josephson junctions was reported experimentally by others, where the Josephson junctions were operated in the classical regime [23,24]. Moreover, it was revisited recently in simple quantum dynamics by the present authors [25].…”

Section: Introductionmentioning

confidence: 85%

Classical and quantum dissipative dynamics in Josephson junctions: An Arnold problem, bifurcation, and capture into resonance

2019

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We theoretically study the phase dynamics in Josephson junctions, which maps onto the oscillatory motion of a point-like particle in the washboard potential. Under appropriate driving and damping conditions, the Josephson phase undergoes intriguing bistable dynamics near a saddle point in the quasienergy landscape. The bifurcation mechanism plays a critical role in superconducting quantum circuits with relevance to non-demolition measurements such as high-fidelity readout of qubit states. We address the question "what is the probability of capture into either basin of attraction" and answer it concerning both classical and quantum dynamics. Consequently, we derive the Arnold probability and numerically analyze its implementation of the controlled dynamical switching between two steady states under the various nonequilibrium conditions.

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TunableφJosephson junction ratchet

Cited by 15 publications

References 46 publications

Spin-orbit-torque-induced magnetic domain wall motion in Ta/CoFe nanowires with sloped perpendicular magnetic anisotropy

Spin-orbit-torque-induced magnetic domain wall motion in Ta/CoFe nanowires with sloped perpendicular magnetic anisotropy

Scaling theory of a quantum ratchet

Classical and quantum dissipative dynamics in Josephson junctions: An Arnold problem, bifurcation, and capture into resonance

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