Unconventional Meissner screening induced by chiral molecules in a conventional superconductor

Abstract

The coupling of a superconductor to a different material often results in a system with unconventional superconducting properties. A conventional superconductor is a perfect diamagnet expelling magnetic fields out of its volume, a phenomenon known as Meissner effect. Here, we show that the simple adsorption of a monolayer of chiral molecules, which are non-magnetic in solution, onto the surface of a conventional superconductor can markedly change its diamagnetic Meissner response. By measuring the internal magnetic field profile in superconducting Nb thin films under an applied transverse field by low-energy muon spin rotation spectroscopy, we demonstrate that the local field profile inside Nb is considerably modified upon molecular adsorption in a way that also depends on the applied field direction. The modification is not limited to the chiral molecules/Nb interface, but it is long ranged and occurs over a length scale comparable to the superconducting coherence length. Zero-field muon spin spectroscopy measurements in combination with our theoretical analysis show that odd-frequency spin-triplet states induced by the chiral molecules are responsible for the modification of the Meissner response observed inside Nb. These results indicate that a chiral molecules/superconductor system supports odd-frequency spin-triplet pairs due to the molecules acting as a spin active layer and therefore they imply that such system can be used as a simpler alternative to superconductor/ferromagnet or superconductor/topological insulator hybrids for the generation and manipulation of unconventional spin-triplet superconducting states.

13 pages and 5 figures plus Appendixes

References in corpus (6)

• Signature of magnetic-dependent gapless odd frequency states at superconductor/ferromagnet interfaces
• Role of Exchange Interactions in the Magnetic Response and Intermolecular Recognition of Chiral Molecules
• Long-Timescale Magnetization Ordering Induced by an Adsorbed Chiral Monolayer on Ferromagnets
• The Meissner effect in a strongly underdoped cuprate above its critical temperature
• Unconventional superconductivity induced in Nb films by adsorbed chiral molecules
• Giant Vortices Below the Surface of NbSe${}_2$ Detected Using Low Energy $\beta$-NMR

Cited by in corpus (8)

• Gate control of superconducting current: Mechanisms, parameters and technological potential
• Depth-resolved measurements of the Meissner screening profile in surface-treated Nb
• Achiral dipoles on a ferromagnet can affect its magnetization direction
• Emergent magnetism as a cooperative effect of interactions and reservoir
• Absence of magnetic interactions in Ni-Nb ferromagnet-superconductor bilayers
• Signatures of a Spin-Active Interface and Locally Enhanced Zeeman field in a Superconductor-Chiral Material Heterostructure
• Equal contribution of even and odd frequency pairing to transport across normal metal-superconductor junctions
• Topological superconductivity in helical crystals