Breaking inversion symmetry in a state-dependent honeycomb lattice: Artificial graphene with tunable band gap

Abstract

Here, we present the application of a novel method for controlling the geometry of a state-dependent honeycomb lattice: The energy offset between the two sublattices of the honeycomb structure can be adjusted by rotating the atomic quantization axis. This enables us to continuously tune between a homogeneous graphene-like honeycomb lattice and a triangular lattice and to open an energy gap at the characteristic Dirac points. We probe the symmetry of the lattice with microwave spectroscopy techniques and investigate the behavior of atoms excited to the second energy band. We find a striking influence of the energy gap at the Dirac cones onto the lifetimes of atoms in the excited band.

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• Magic-Angle Semimetals with Chiral Symmetry
• Topological flat bands in time-periodically driven uniaxial strained graphene nanoribbons
• Topological edge states on time-periodically strained armchair graphene nanoribbons
• Observation of topological Bloch-state defects and their merging transition
• Quantum degenerate Fermi gas in an orbital optical lattice
• High-precision multiband spectroscopy of ultracold fermions in a nonseparable optical lattice
• Proximity effects in cold atom artificial graphene
• Multi-frequency optical lattice for dynamic lattice-geometry control
• Intrinsic Anomalous Hall Effect in a Bosonic Chiral Superfluid
• Topological phase-diagram of time-periodically rippled zigzag graphene nanoribbons
• Floquet topological phase transitions in a kicked Haldane-Chern insulator
• Tunable valley filtering in dynamically strained $\alpha$-${\mathcal{T}}_3$ lattices
• Experimental realization of a high precision tunable hexagonal optical lattice
• Intrinsic anomalous Hall effect across the magnetic phase transition of a spin-orbit-coupled Bose-Einstein condensate