Dependence of the superconducting transition temperature on the electronic density of states and lattice parameter in pulsed laser deposited niobium nitride thin films
File(s)
Published version
Author(s)
Cohen, Lesley
Type
Journal Article
Abstract
High quality epitaxial niobium nitride (NbN) thin films were grown on MgO (001) substrates by pulsed laser deposition (PLD) from a pure NbN target while varying the nitrogen partial pressure inside the chamber. This variation provides an additional degree of freedom in the film formation: by adjusting the nitrogen partial pressure, we modify the lattice parameter of the ∂-NbN phase systematically, and tune the superconducting transition temperature (Tc). X-ray Diffraction and Hall conductivity measurements show that this change in Tc arises from the combined influence of lattice strain, and carrier concentration. A phenomenological analysis based on the McMillan and Allen Dynes strong coupling models closely captures the observed trends. Our results demonstrate that rational design of epitaxial superconducting materials, essential for interface control of physical properties, can be achieved by tuning the lattice parameter and carrier concentration in ∂-NbN. Furthermore, our results provide a pathway to separate intrinsic structural factors affecting the transition temperature from proximity-induced effects in superconducting hybrid structures.
Date Issued
2026-05-01
Date Acceptance
2026-04-20
Citation
Superconductor Science and Technology, 2026, 39 (5)
ISSN
0953-2048
Publisher
IOP Publishing
Journal / Book Title
Superconductor Science and Technology
Volume
39
Issue
5
Copyright Statement
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
License URL
Identifier
10.1088/1361-6668/ae61fe
Subjects
pulsed laser deposition
NbN thin films
unconventional superconductivity
Publication Status
Published
Article Number
055007
Date Publish Online
2026-05-08