Sublattice-selective interlayer hybridizations in twisted bipartite lattice heterobilayers generate tunable zero-energy flat bands possessing finite Berry curvature and Chern-insulator-scale quantum metric.
Experimental realization of dice-lattice flat band at the Fermi level in layered electride YCl
3 Pith papers cite this work. Polarity classification is still indexing.
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abstract
Flat electronic bands, where interactions among electrons overwhelm their kinetic energies, hold the promise for exotic correlation physics. The dice lattice has long been theorized as a host of flat bands with intriguing band topology. However, to date, no material has ever been found to host the characteristic flat bands of a dice lattice. Here, using angle-resolved photoemission spectroscopy (ARPES), we discover a dice-lattice flat band at $E_F$ in the van der Waals (vdW) electride [YCl]$^{2+}$: 2e-. In this system, excess valence electrons from Y deconfine from the cation framework to form an interstitial anionic electron lattice that constitutes the dice lattice. Our ARPES measurements unambiguously identify two sets of dice-lattice bands in YCl, including a nearly dispersionless band at the Fermi level. The flat bands and other dispersive bands observed in ARPES find excellent agreement with first-principles calculations, and theoretical analysis reveals that the near-$E_F$ electronic structure is well captured by a simple dice-lattice model. Our findings thus end the long quest of a real dice flat band material and establish vdW electride YCl as a prototype of dice metals. Our results further demonstrate the anionic electron lattice as a novel scheme for realizing lattice geometries and electronic structures rare to find in conventional crystalline systems.
verdicts
UNVERDICTED 3representative citing papers
In the α-T3 lattice with on-site asymmetry, mean-field theory shows a superconducting gap that grows as a power law with interaction strength at flat-band filling, while the geometric part of the superfluid weight grows linearly and is enhanced by tuning α.
YCl requires a multi-orbital description for its dice lattice flat band, predicting ferromagnetic ground state and tunable correlated QAH phases absent in single-orbital models.
citing papers explorer
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Quantum Geometry of Moir\'e Flat Bands Beyond the Valley Paradigm
Sublattice-selective interlayer hybridizations in twisted bipartite lattice heterobilayers generate tunable zero-energy flat bands possessing finite Berry curvature and Chern-insulator-scale quantum metric.
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Superconductivity and geometric superfluid weight of a tunable flat band system
In the α-T3 lattice with on-site asymmetry, mean-field theory shows a superconducting gap that grows as a power law with interaction strength at flat-band filling, while the geometric part of the superfluid weight grows linearly and is enhanced by tuning α.
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YCl Electride as a Multi-Orbital Correlated Topological Dice Lattice System
YCl requires a multi-orbital description for its dice lattice flat band, predicting ferromagnetic ground state and tunable correlated QAH phases absent in single-orbital models.