Title: Hot-lines topology and the fate of the spin resonance mode in three-dimensional unconventional superconductors

Abstract

In the quasi-two-dimensional (quasi-2D) copper- and iron-based superconductors, the onset of superconductivity is accompanied by a prominent peak in the magnetic spectrum at momenta close to the wave-vector of the nearby antiferromagnetic state. Such a peak is well described in terms of a spin resonance mode, i.e., a spin-1 exciton theoretically predicted for quasi-2D superconductors with a sign-changing gap. The same theories, however, indicate that such a resonance mode should be absent in a three-dimensional (3D) system with a spherical Fermi surface. This raises the question of the fate of the spin resonance mode in layered unconventional superconductors that are not strongly anisotropic, such as certain heavy-fermion compounds and potentially the newly discovered nickelate superconductor NdNiO₂. Here, we use the random phase approximation to calculate the dynamical spin susceptibility of 3D superconductors with a d_x²–y²-wave gap symmetry and corrugated cylindrical-like Fermi surfaces. By varying the out-of-plane hopping anisotropy t_z/t, we demonstrate that the appearance of a spin resonance mode is determined by the topology of the hot lines, i.e., lines on the Fermi surface that are connected by the magnetic wave vector. For an in-plane antiferromagnetic wave vector, the hot lines undergo a topological transition from open lines to closedmore » loops at a critical t_z/t value. The closed hot lines cross the nodal superconducting lines, making the spin resonance mode overdamped and incoherent. In contrast, for an out-of-plane antiferromagnetic wave vector, the hot lines remain open and the spin resonance mode remains sharp. We discuss the experimental implications of our results for the out-of-plane dispersion of the spin resonance mode and, more generally, for inelastic neutron scattering experiments on unconventional superconductors.« less

Authors:

Chen, Fei  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-7801-4814"

Fernandes, Rafael M. ^[1]; Christensen, Morten H.  ^[2]

• Search DOE PAGES for author "Christensen, Morten H."
• Search DOE PAGES for ORCID "0000-0002-3185-6552"

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+ Show Author Affiliations

1. Univ. of Minnesota, Minneapolis, MN (United States)
2. Univ. of Copenhagen (Denmark). The Niels Bohr Inst.

Publication Date:

Mon Jul 18 00:00:00 EDT 2022

Research Org.:

Univ. of Minnesota, Minneapolis, MN (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1979788

Grant/Contract Number:  

SC0016371

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review. B

Additional Journal Information:

Journal Volume: 106; Journal Issue: 1; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Physics; magnetic susceptibility; superconductivity; unconventional superconductors