Cavity-altered superconductivity

Area of Science:

• Quantum Materials Science
• Condensed Matter Physics
• Nanophotonics

Background:

• Altering material properties via electromagnetic environments is theoretically predicted.
• Experimental realization of cavity-controlled properties without optical excitation is emerging.
• Hyperbolic van der Waals (vdW) crystals offer unique electromagnetic environments.

Purpose of the Study:

• To investigate the feasibility of engineering a material's ground-state properties by manipulating its electromagnetic environment.
• To develop a novel platform for realizing cavity-altered materials.
• To explore resonant coupling between hyperbolic modes and molecular resonances.

Main Methods:

• Interfacing hexagonal boron nitride (hBN) with the molecular superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br (κ-ET).
• Utilizing nano-optical measurements and first-principles molecular Langevin dynamics simulations.
• Performing Meissner-effect measurements using magnetic force microscopy (MFM).

Main Results:

• Confirmed resonant coupling between hBN hyperbolic cavity modes and κ-ET's C=C stretching mode.
• Demonstrated significant suppression of superfluid density at the hBN/κ-ET interface.
• Observed no pronounced superfluid suppression in non-resonant control heterostructures.

Conclusions:

• The hBN/κ-ET heterostructure realizes a cavity-altered superconducting ground state.
• This work highlights the potential of dark cavities for engineering quantum material properties.
• Cavity quantum electrodynamics principles can be applied to modify electronic ground states.