RKKY couplings in the Lieb lattice: flat-band induced frustration

Abstract

Despite their dispersion-less character, flat bands (FBs) are often at the heart of remarkable physical phenomena. Because, FBs may be responsible for unconventional quantum electronic transport, our purpose is to investigate their impact on the RKKY couplings (J(R)). As a good candidate, we choose the The Lieb lattice which consists of one four-fold coordinated atom (A) and two two-fold coordinated atoms (B,C) per unit cell. As in graphene, at the neutrality point, J(R) is found to fall off as 1/R3. The coupling between a pair of impurities on sublattice A are found ferromagnetic and isotropic. In contrast, for impurities on the two-fold coordinated sites, J(R) reveals (i) a strong angular anisotropy and (ii) can be both ferromagnetic (F) or antiferromagnetic (AF). The AF character introduced by the FB can largely dominate, and introduces frustration effects. The FB is found to have a drastic impact on J(R) for impurities located on (B,C) sublattices. We have also addressed the effect of tuning the carrier density that reveals remarkable features as well.

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References in corpus (16)

• High temperature fractional quantum Hall states
• Fractional quantum Hall states at zero magnetic field
• Nearly-flat bands with nontrivial topology
• Tunable Phase Boundaries and Ultra-Strong Coupling Superconductivity in Mirror Symmetric Magic-Angle Trilayer Graphene
• Flat bands and Wigner crystallization in the honeycomb optical lattice
• Topological flat bands in frustrated kagome lattice CoSn
• RKKY in half-filled bipartite lattices: graphene as an example
• RKKY Interaction in Graphene from Lattice Green's Function
• Model for vacancy-induced d${}^0$ ferromagnetism in oxide compounds
• Fragile topology and flat-band superconductivity in the strong-coupling regime
• Flat band superconductivity in the square-octagon lattice
• Flat bands and nontrivial topological properties in an extended Lieb lattice
• Spectroscopy of a Tunable Moiré System with a Correlated and Topological Flat Band
• Quantum transport in flat bands and super-metallicity
• Flat bands and $Z_2$ topological phases in a non-Abelian kagome lattice
• On the Ruderman-Kittel-Kasuya-Yosida interaction in graphene

Cited by in corpus (2)

• Flat band induced room temperature ferromagnetism in two dimensional systems
• RKKY interaction in one-dimensional flat-band lattices