Evidence for chiral superconductivity on a silicon surface

Abstract

Sn adatoms on a Si(111) substrate with 1/3 monolayer coverage form a two-dimensional triangular adatom lattice with one unpaired electron per site and an antiferromagnetic Mott insulating state. The Sn layers can be modulation hole-doped and metallized using heavily-doped $p$-type Si(111) substrates, and become superconducting at low temperatures. While the pairing symmetry of the superconducting state is currently unknown, the combination of repulsive interactions and frustration inherent to the triangular adatom lattice opens up the possibility for a chiral order parameter. Here, we study the superconducting state of Sn/Si(111) using scanning tunneling microscopy/spectroscopy and quasi-particle interference imaging. We find evidence for a doping-dependent $T_c$ with a fully gapped order parameter, the presence of time-reversal symmetry breaking, and a strong enhancement of the zero-bias conductance near the edges of the superconducting domains. While each individual piece of evidence could have a more mundane interpretation, our combined results suggest the tantalizing possibility that Sn/Si(111) is an unconventional chiral d-wave superconductor.

References in corpus (5)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Chiral P-Wave Order in Sr_2RuO_4
• Realization of a hole-doped Mott insulator on a triangular silicon lattice
• Nodal $d+id$ pairing and topological phases on the triangular lattice: unconventional superconducting state of Na${}_x$CoO${}_2\cdot y$H${}_2$O
• Impurity and interface bound states in $d_{x^2-y^2}+i{d}_{xy}$ and $p_x+i{p}_y$ superconductors

Cited by in corpus (24)

• Signatures of Chiral Superconductivity in Rhombohedral Graphene
• Superconducting diode effect and interference patterns in Kagome CsV3Sb5
• Doping-dependent charge- and spin-density wave orderings in a monolayer of Pb adatoms on Si(111)
• Adatom engineering magnetic order in superconductors: Applications to altermagnetic superconductivity
• Coreless vortices as direct signature of chiral $d$-wave superconductivity
• Robust and tunable coreless vortices and fractional vortices in chiral $d$-wave superconductors
• Enhanced chiral edge currents and orbital magnetic moment in chiral $d$-wave superconductors from mesoscopic finite-size effects
• Strain-induced superfluid transition for atoms on graphene
• Electronic correlations in epitaxial graphene: Mott states proximitized to a relativistic electron gas
• Friedel oscillations and chiral superconductivity in monolayer NbSe${}_2$
• Fingerprints of a charge ice state in the doped Mott insulator Nb${}_3$Cl${}_8$
• Thermomodulated intrinsic Josephson effect in Kagome CsV3Sb5
• Magnetism and superconductivity in doped triangular-lattice Mott insulators
• Optimizing the Critical Temperature and Superfluid Density of a Metal-Superconductor Bilayer
• Chern number landscape of spin-orbit coupled chiral superconductors
• Electronic structure, spin-orbit interaction and electron-phonon coupling of triangular adatom lattices on semiconductor substrates
• Magnetic field induced partially polarized chiral spin liquid in a transition metal dichalcogenide moiré system
• Angular momentum of vortex-core Majorana zero modes
• The electronic structure of a doped Mott-Hubbard surface
• Searching for superconductivity in doped triangular lattice Kitaev magnets
• Real-Space Switching of Local Moments Driven by Quantum Geometry in Correlated Graphene Heterostructures
• Engineering correlated Dirac fermions and flat bands on SiC with transition-metal adatom lattices
• Anisotropic transport of Josephson vortices in atomic-layer superconductors on vicinal surfaces
• Designing edge currents using mesoscopic patterning in chiral d-wave superconductors