# Microscopic Theory of Pinning of Multiquantum Vortex in Cylindrical Cavity

## Abstract

We have proposed and developed a microscopic model of depinning (escape) of a multiquantum vortex in a superconductor with a cylindrical nonconducting cavity with the transverse size smaller than or on the order of the superconducting coherence length ξ{sub 0} at zero temperature. The spectrum of subgap quasiparticle excitations in two- and three-quantum vortices trapped by a cylindrical cavity has been calculated in the quasiclassical approximation. It is shown that the transformation of the spectrum is accompanied by break of anomalous spectral branches due to normal reflection of quasiparticles from the surface of a defect. A microscopic (spectral) criterion for multiquantum vortex pinning has been proposed; according to this criterion, the multiquantum vortex can be trapped in the cavity during the formation of a minigap in the elementary excitation spectrum near the Fermi level. Self-consistent calculations of density of states N(r, ε) for two- and three-quantum vortices trapped by a cylindrical cavity of radius on the order of ξ{sub 0} have been performed using quasiclassical Eilenberger equations. In the pure limit and for low temperatures T ≪ T{sub c}, peculiarities observed in the N(r, ε) distribution reflect the presence of M anomalous spectral branches in the M-quantum vortex and confirmmore »

- Authors:

- Russian Academy of Sciences, Institute of Physics of Microstructures (Russian Federation)

- Publication Date:

- OSTI Identifier:
- 22750018

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Experimental and Theoretical Physics

- Additional Journal Information:
- Journal Volume: 126; Journal Issue: 2; Other Information: Copyright (c) 2018 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1063-7761

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COHERENCE LENGTH; CYLINDRICAL CONFIGURATION; DENSITY OF STATES; FERMI LEVEL; QUASI PARTICLES; TRAPPING; VORTICES

### Citation Formats

```
Samokhvalov, A. V., E-mail: samokh@ipmras.ru, and Melnikov, A. S..
```*Microscopic Theory of Pinning of Multiquantum Vortex in Cylindrical Cavity*. United States: N. p., 2018.
Web. doi:10.1134/S1063776118020048.

```
Samokhvalov, A. V., E-mail: samokh@ipmras.ru, & Melnikov, A. S..
```*Microscopic Theory of Pinning of Multiquantum Vortex in Cylindrical Cavity*. United States. doi:10.1134/S1063776118020048.

```
Samokhvalov, A. V., E-mail: samokh@ipmras.ru, and Melnikov, A. S.. Thu .
"Microscopic Theory of Pinning of Multiquantum Vortex in Cylindrical Cavity". United States. doi:10.1134/S1063776118020048.
```

```
@article{osti_22750018,
```

title = {Microscopic Theory of Pinning of Multiquantum Vortex in Cylindrical Cavity},

author = {Samokhvalov, A. V., E-mail: samokh@ipmras.ru and Melnikov, A. S.},

abstractNote = {We have proposed and developed a microscopic model of depinning (escape) of a multiquantum vortex in a superconductor with a cylindrical nonconducting cavity with the transverse size smaller than or on the order of the superconducting coherence length ξ{sub 0} at zero temperature. The spectrum of subgap quasiparticle excitations in two- and three-quantum vortices trapped by a cylindrical cavity has been calculated in the quasiclassical approximation. It is shown that the transformation of the spectrum is accompanied by break of anomalous spectral branches due to normal reflection of quasiparticles from the surface of a defect. A microscopic (spectral) criterion for multiquantum vortex pinning has been proposed; according to this criterion, the multiquantum vortex can be trapped in the cavity during the formation of a minigap in the elementary excitation spectrum near the Fermi level. Self-consistent calculations of density of states N(r, ε) for two- and three-quantum vortices trapped by a cylindrical cavity of radius on the order of ξ{sub 0} have been performed using quasiclassical Eilenberger equations. In the pure limit and for low temperatures T ≪ T{sub c}, peculiarities observed in the N(r, ε) distribution reflect the presence of M anomalous spectral branches in the M-quantum vortex and confirm the correctness of the spectral criterion of pinning (depinning) of a multiquantum vortex.},

doi = {10.1134/S1063776118020048},

journal = {Journal of Experimental and Theoretical Physics},

issn = {1063-7761},

number = 2,

volume = 126,

place = {United States},

year = {2018},

month = {2}

}