Eur. Phys. J. Special Topics 227, 2289–2295 (2019)
https://doi.org/10.1140/epjst/e2018-800046-x

Regular Article

Quantum fluctuations and density of states in low-dimensional superconductors

¹ I.E. Tamm Department of Theoretical Physics, P.N. Lebedev Physical Institute, 119991 Moscow, Russia
² National Research University Higher School of Economics, 101000 Moscow, Russia
³ Institute of Nanotechnology, Karlsruhe Institute of Nanotechnology (KIT), 76021 Karlsruhe, Germany

^a e-mail: radkevich@lpi.ru

Received: 10 April 2018
Received in final form: 13 July 2018
Published online: 18 January 2019

Abstract

We investigate the influence of quantum phase fluctuations on electron density of states (DOS) in ultrathin superconducting films and nanowires. Using an effective action approach we derive a non-perturbative correction to DOS in such systems. The main effect of phase fluctuations in quasi-two-dimensional films is the appearance of electron states at subgap energies while in quasi-one-dimensional nanowires fluctuations also lead to smearing of the gap edge singularity in DOS.