Vortex ratchet image


Superconducting vortex ratchets

When an overdamped particle is placed in an asymmetric potential and an additional ac drive is applied, a net dc drift velocity or rectification can occur which is known as the ratchet effect. Stochastic ratchets can be constructed with Brownian particles, while ordinary ratchets can be created in deterministic systems. Typically, an applied ac drive or periodic flashing of the potential couples with some form of asymmetry in the substrate, breaking the symmetry of the particle motion. We study a variety of vortex ratchet effects, ranging from ac rocking ratchets, in which the rectification of the vortex motion arises due to an asymmetry in the pinning landscape, to noise correlation ratchets, in which ratcheting motion occurs in a direction with no landscape asymmetry due to the generation of nonequilibrium noise through vortex plastic flow. Often, collective interactions between the vortices can produce reversals in the ratchet flow.

Preprints:

  1. Achieving 100% superconducting diode efficiency with AC electrical excitation in 2D nano-device
    D. Berube, T. Faeth, K. Rigaux, Y. Fang, A. Gao, Y.-F. Liu, T. Dinh, J.-X. Qiu, H. Li, K. Watanabe, T. Taniguchi, F. Huang, C.J.O. Reichhardt, C. Reichhardt, and S.-Y. Xu
    Superconducting diodes are an important part of multiple technologies, from energy-efficient superconducting computing to large scale quantum computing, memories and switches. In this paper, we report a magnetic-field-free, tunable, and perfictly rectifying superconducting diode by applying an additional AC electrical excitation to a centrosymmetric 2M-WS2 sample with a tear running through it. Proceeding incrementally, we first demonstrate diode efficiencies up to 30% at 90mT and calculate a magnetochiral anisotropy coefficient of γ=6.0x108 T-1A-1, the highest ever reported. The most significant takeaway comes as we investigate a novel geometry: an AC drive applied perpendicular to the direction of current. At large AC drives, and under no external field, we find Ic+=0 while Ic-=2μA, a 100% diode efficiency. Simulations suggest that a strongly asymmetric ratchet effect is induced by the AC drive. The tear enables an easy vortex flow for one DC current direction, but presents a barrier to motion under opposite bias polarity. In simulations, we explicitly demonstrate increasing diode efficiency with increasing AC drive. Since these effects depend on vortex motion through a generic superconducting slab with a tear creating an asymmetry, they are generalizable: the new AC drive geometry could be a novel tuning knob to adjust and enhance diode efficiency.


Papers:

  1. Pinning, flux diodes, and ratchets for vortices interacting with conformal pinning arrays
     C.J. Olson Reichhardt, Y.L. Wang, Z.L. Xiao, W.K. Kwok, D. Ray, C. Reichhardt, and B. Janko
    Physica C 533, 148 (2017). arXiv


  2. Transverse ac-driven and geometric ratchet effects for vortices in conformal crystal pinning arrays
     C. Reichhardt and C.J. Olson Reichhardt
    Phys. Rev. B 93, 064508 (2016). arXiv


  3. Reversible ratchet effects for vortices in conformal pinning arrays
     C. Reichhardt, D. Ray, and C.J. Olson Reichhardt
    Phys. Rev. B 91, 184502 (2015). arXiv


  4. Vortex clogging, commensuration, and diodes in asymmetric constriction arrays
    C.J. Olson Reichhardt and C. Reichhardt
    J. Supercond. Nov. Magn. 26, 2005 (2013).


  5. Jamming and diode effects for vortices in nanostructured superconductors
    C. Reichhardt and C.J. Olson Reichhardt
    Physica C 470, 722 (2010).


  6. Origin of reversed vortex ratchet motion
    W. Gillijns, A.V. Silhanek, V.V. Moshchalkov, C.J. Olson Reichhardt, and C. Reichhardt
    Phys. Rev. Lett. 99, 247002 (2007). arXiv


  7. Ratchet cellular automata and logic devices
    C.J. Olson Reichhardt, C. Reichhardt, and B. Janko
    IEEE 2007 Proc. Int. Conf. Electromagnetics Adv. Applications (ICEAA), p. 625 (2007).


  8. Reversible vortex ratchet effects and ordering in superconductors with simple asymmetric potential arrays
    Qiming Lu, C.J. Olson Reichhardt, and C. Reichhardt
    Phys. Rev. B 75, 054502 (2007). arXiv


  9. Rectification and flux reversals for vortices interacting with triangular traps
    C.J. Olson Reichhardt and C. Reichhardt
    Physica C 432, 125 (2005). arXiv


  10. Ratchet effects for vortices in superconductors with periodic pinning arrays
    C. Reichhardt and C.J. Olson Reichhardt,
    Physica C 404, 302 (2004). arXiv


  11. Ratchet superconducting vortex cellular automata
    C.J. Olson Reichhardt, C. Reichhardt, M.B. Hastings, and B. Janko,
    Physica C 404, 266 (2004).


  12. Ratchet cellular automata
    M.B. Hastings, CJ. Olson Reichhardt, and C. Reichhardt,
    Phys. Rev. Lett. 90, 247004 (2003). arXiv


  13. Collective interaction-driven ratchet for transporting flux quanta
    C.J. Olson, C. Reichhardt, B. Janko, and F. Nori
    Phys. Rev. Lett. 87, 177002 (2001). arXiv


  14. Superconducting fluxon pumps and lenses
     J.F. Wambaugh, C. Reichhardt, C.J. Olson, F. Marchesoni, and F. Nori
    Phys. Rev. Lett. 83, 5106 (1999). arXiv


Experimental realization of RCA:

Last modified May 3, 2018