Real B, Jamadi O, Milićević M, Pernet N, St-Jean P, Ozawa T, Montambaux G, Sagnes I, Lemaître A, Le Gratiet L, Harouri A, Ravets S, Bloch J, Amo A
Univ. Lille, CNRS, UMR 8523-PhLAM-Physique des Lasers Atomes et Molécules, F-59000 Lille, France.
Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France.
Phys Rev Lett. 2020 Oct 30;125(18):186601. doi: 10.1103/PhysRevLett.125.186601.
Compression dramatically changes the transport and localization properties of graphene. This is intimately related to the change of symmetry of the Dirac cone when the particle hopping is different along different directions of the lattice. In particular, for a critical compression, a semi-Dirac cone is formed with massless and massive dispersions along perpendicular directions. Here we show direct evidence of the highly anisotropic transport of polaritons in a honeycomb lattice of coupled micropillars implementing a semi-Dirac cone. If we optically induce a vacancylike defect in the lattice, we observe an anisotropically localized polariton distribution in a single sublattice, a consequence of the semi-Dirac dispersion. Our work opens up new horizons for the study of transport and localization in lattices with chiral symmetry and exotic Dirac dispersions.
压缩显著改变了石墨烯的输运和局域性质。这与当粒子在晶格的不同方向上跳跃不同时狄拉克锥对称性的变化密切相关。特别是，对于临界压缩，会形成一个半狄拉克锥，其在垂直方向上具有无质量和有质量的色散。在此，我们展示了在实现半狄拉克锥的耦合微柱蜂窝晶格中极化激元高度各向异性输运的直接证据。如果我们在晶格中光学诱导出类似空位的缺陷，我们会在单个子晶格中观察到各向异性局域的极化激元分布，这是半狄拉克色散的结果。我们的工作为研究具有手性对称性和奇异狄拉克色散的晶格中的输运和局域开辟了新的视野。
