Recent progress on superconductors with time-reversal symmetry breaking

SK Ghosh, M Smidman, T Shang… - Journal of Physics …, 2020 - iopscience.iop.org
Superconductivity and magnetism are adversarial states of matter. The presence of
spontaneous magnetic fields inside the superconducting state is, therefore, an intriguing …

Superconducting vortices carrying a temperature-dependent fraction of the flux quantum

Y Iguchi, RA Shi, K Kihou, CH Lee, M Barkman… - Science, 2023 - science.org
Magnetic field penetrates type-II bulk superconductors by forming quantum vortices that
enclose a magnetic flux equal to the magnetic flux quantum. The flux quantum is a universal …

Superconductivity with broken time-reversal symmetry inside a superconducting s-wave state

V Grinenko, R Sarkar, K Kihou, CH Lee, I Morozov… - Nature Physics, 2020 - nature.com
In general, magnetism and superconductivity are antagonistic to each other. However, there
are several families of superconductors in which superconductivity coexists with magnetism …

Calorimetric evidence for two phase transitions in Ba1−xKxFe2As2 with fermion pairing and quadrupling states

I Shipulin, N Stegani, I Maccari, K Kihou… - Nature …, 2023 - nature.com
Materials that break multiple symmetries allow the formation of four-fermion condensates
above the superconducting critical temperature (T c). Such states can be stabilized by phase …

Demonstration of skyrmions in three-band superconductors by self-consistent solutions of a Bogoliubov–de Gennes model

A Benfenati, M Barkman, E Babaev - Physical Review B, 2023 - APS
Topological defects, such as magnetic-flux-carrying quantum vortices, determine the
magnetic response of superconductors and hence are of fundamental importance. Here, we …

Hydrodynamics of Borromean counterfluids

E Babaev, B Svistunov - Physical Review Letters, 2024 - APS
Counterflow superfluidity in a system with N≥ 3 components is distinctively different from the
N= 2 case. The key feature is the difference between the number (N) of elementary vortex …

Properties of dirty two-band superconductors with repulsive interband interaction: Normal modes, length scales, vortices, and magnetic response

J Garaud, A Corticelli, M Silaev, E Babaev - Physical Review B, 2018 - APS
Disorder in two-band superconductors with repulsive interband interaction induces a
frustrated competition between the phase-locking preferences of the various potential and …

Effective model and magnetic properties of the resistive electron quadrupling state

J Garaud, E Babaev - Physical Review Letters, 2022 - APS
Recent experiments [Grinenko et al. Nat. Phys. 17, 1254 (2021) NPAHAX 1745-2473
10.1038/s41567-021-01350-9] reported the observation of a condensate of four-fermion …

Effects of intercomponent couplings on the appearance of time-reversal symmetry breaking fermion-quadrupling states in two-component london models

I Maccari, E Babaev - Physical Review B, 2022 - APS
Detection of a bosonic metallic state that breaks the Z 2 time-reversal symmetry has been
recently reported in Ba 1− x K x Fe 2 As 2 with a doping level x≈ 0.8. This is a metallic state …

Magnetic signatures of domain walls in and superconductors: Observability and what that can tell us about the superconducting order parameter

A Benfenati, M Barkman, T Winyard, A Wormald… - Physical Review B, 2020 - APS
One of the defining features of spontaneously broken time-reversal symmetry (BTRS) is the
existence of domain walls, the detection of which would be strong evidence for such …