Soliton states in mesoscopic two-band-superconducting cylinders

Abstract

In the framework of the Ginzburg-Landau approach, we present a self-consistent theory of specific soliton states in mesoscopic (thin-walled) two-band-superconducting cylinders in external parallel magnetic fields. Such states arise in the presence of "Josephson-type" interband coupling, when phase winding numbers are different for each component of the superconducting order parameter. We evaluate the Gibbs free energy of the sysyem up to second-order terms in a certain dimensionless parameter ε ≈ Lm L k ≪ 1, where Lm and L k are the magnetic and kinetic inductance, respectively. We derive the complete set of exact soliton solutions. These solutions are thoroughly analyzed from the viewpoint of both local and global (thermodynamic) stability. In particular, we show that rotational-symmetry-breaking caused by the formation of solitons gives rise to a zero-frequency rotational mode. Although soliton states prove to be thermodynamically metastable, the minimal energy gap between the lowest-lying single-soliton states and thermodynamically stable zero-soliton states can be much smaller than the magnetic Gibbs free energy of the latter states, provided that intraband "penetration depths" differ substantially and interband coupling is weak. The results of our investigation may apply to a wide class of mesoscopic doubly-connected structures exhibiting two-band superconductivity.

Observation of quantum oscillations in a narrow channel with a hole fabricated on a film of multiband superconductors

“…In this situation, the formation of a chiral domain played a similar role as a soliton. Kuplevakhsky, Omelyanchouk and Yerin theoretically demonstrated that the phase shift was caused by the formation of a soliton in the ring of an intrinsic multiband superconductor [6]. This provides a plausible explanation for our experimental results.…”

“…[4] Moler and co-workers reported such an obstruction in a mimic multi-band superconductor composed of an AlO x insulating layer sandwiched between two Al layers with a two component function, making them bilayers [5]. Kuplevakhsky, Omelyanchouk and Yerin suggested that this obstruction is expected in intrinsic multiband superconductors [6]. Current superconducting electronics and devices are based on a single order parameter scheme.…”

“…Kuplevakhsky, Omelyanchouk and Yerin suggested that this obstruction is expected in intrinsic multiband superconductors [6]. Current superconducting electronics and devices are based on a single order parameter scheme.…”

BCS-BEC Crossover and Pairing Fluctuations in a Two Band Superfluid/Superconductor: A T Matrix Approach

“…From the theoretical viewpoint, a variety of non-trivial phenomena has been proposed (e.g., topological phase soliton [7,8], odd-frequency pairing [9], multiple Leggett mode [10], hidden criticality [11], stable Sarma phase [12], and Lifshitz transitions with resonance effects and amplification of the critical temperature [13,14]).…”

Fluxon dynamics of a long Josephson junction with two-gap superconductors

“…Kupulevaksky and coworkers examined 18 this soliton state in mesoscopic thin-walled cylinders in external magnetic fields by using the Ginzberg-Landau approach,. Tanaka and coworkers suggested 19 that interesting excitations, including a phase domain surrounded by the i-soliton wall, can arise in two dimensions (i.e., D=2) since an i-soliton may be considered as a D-1 dimensional quantum phase dislocation.…”