Dirac-Weyl fermions with arbitrary spin in two-dimensional optical superlattices

作者：Zhihao Lan, Nathan Goldman, A. Bermúdez, Wenjing Lu, Patrik Öhberg · 发表于：Physical Review B · 年份：2011 · DOI：10.1103/physrevb.84.165115 · 被引用次数：120 · 研究领域：Topological Materials and Phenomena、Cold Atom Physics and Bose-Einstein Condensates、Quantum and electron transport phenomena

Dirac-Weyl fermions are massless relativistic particles with a well-defined helicity which arise in the context of high-energy physics. Here we propose a quantum simulation of these paradigmatic fermions using multicomponent ultracold atoms in a two-dimensional square optical lattice. We find that laser-assisted spin-dependent hopping, specifically tuned to the $(2s+1)$-dimensional representations of the $\mathfrak{su}$(2) Lie algebra, directly leads to a regime where the emerging massless excitations correspond to Dirac-Weyl fermions with arbitrary pseudospin $s$. We show that this platform hosts two different phases: a semimetallic phase that occurs for half-integer $s$, and a metallic phase that contains a flat zero-energy band at integer $s$. These phases host a variety of interesting effects, such as a very rich anomalous quantum Hall effect and a remarkable multirefringent Klein tunneling. In addition, we show that these effects are directly related to the number of underlying Dirac-Weyl species and zero modes.