Presentation Information
[PC6-03]Generation of Vortices by Current Injection into Mesoscopic Superconductors: Numerical Study
Shota Oshiro1, Ayumu Takahashi1, Takumi Mataba1, Masahiko Hayashi2, *Akinobu Kanda1 (1. Univ. Tsukuba (Japan), 2. Akita Univ. (Japan))
Keywords:
Mesoscopic superconductors,Vortex,Current Injection
[Purpose] Due to their high-speed operation and low power consumption, superconducting digital devices are important for classical and quantum computing. However, small (micro-meter-sized) memory devices that operate at low temperatures have not yet been implemented. Abrikosov vortices in mesoscopic superconductors with sizes approaching superconducting coherence length are one of the promising candidates for information carriers in low temperature memory devices. In mesoscopic superconductors, the number of vortices and their configurations strongly depends on the sample shape,1) and applied magnetic field, and can be controlled by current injection.2) Here, to explore the possibility of applying vortices in mesoscopic superconductors to memory devices, we numerically investigate basic properties of vortex states under current injection.
[Method] We used a program, pyTDGL,3) which solves the TDGL equation for two-dimensional superconductors for the simulation. The sample is a square superconductor with a side length of 1.1 μm and a thickness of 40 nm with superconducting leads 0.3 μm wide attached to the centers of two opposite sides. We assumed an aluminum film under zero magnetic field.
[Results] When there is no surfave defects on the sides, a vortex and an antivortex form at the center of the square, move in opposite directions and then exit the sample. One the other hand, when a surface defect exists at the center of the left side, under a current injection, a vortex enters at the position of the surface defect and pass across the sample.
[Conclusion] Our results indicate that surface defects strongly influence vortex generations. In the presentation, we will focus on the effect of surface defects and holes on the vortex states and their stabilities and discuss the realization of vortex memories.
[Method] We used a program, pyTDGL,3) which solves the TDGL equation for two-dimensional superconductors for the simulation. The sample is a square superconductor with a side length of 1.1 μm and a thickness of 40 nm with superconducting leads 0.3 μm wide attached to the centers of two opposite sides. We assumed an aluminum film under zero magnetic field.
[Results] When there is no surfave defects on the sides, a vortex and an antivortex form at the center of the square, move in opposite directions and then exit the sample. One the other hand, when a surface defect exists at the center of the left side, under a current injection, a vortex enters at the position of the surface defect and pass across the sample.
[Conclusion] Our results indicate that surface defects strongly influence vortex generations. In the presentation, we will focus on the effect of surface defects and holes on the vortex states and their stabilities and discuss the realization of vortex memories.