Year: 2005
Type: article
Abstract: We show numerically that, in a Josephson ladder with periodic boundary conditions and subject to a suitable transverse magnetic field, a vortex excitation can spontaneously breakup into two or more fractional excitations. If the ladder has $N$ plaquettes, and $N$ is divisible by an integer $q$, then in an applied transverse field of $1∕q$ flux quanta per plaquette the ground state is a regular pattern of one fluxon every $q$ plaquettes. When one additional fluxon is added to the ladder, it breaks up into $q$ fractional fluxons, each carrying $1∕q$ units of vorticity. The fractional fluxons are basically walls between different domains of the ground state of the underlying $1∕q$ lattice. The fractional fluxons are all depinned at the same applied current and move as a unit. For certain applied fields and ladder lengths, we show that there are isolated fractional fluxons. It is shown that the fractional fluxons would produce a time-averaged voltage related in a characteristic way to the ac voltage frequency.
Source: Physical Review B
Authors: I. Tornes, D. Stroud
Institution: The Ohio State University
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2127779895