标题：Dirac cones in a snub trihexagonal tiling lattice with reflective symmetry breaking
作者：Yang, Bo; Zhang, Xiaoming; Wang, Aizhu; Zhao, Mingwen
作者机构：[Yang, Bo; Zhang, Xiaoming; Zhao, Mingwen] Shandong Univ, Sch Phys, Jinan 250100, Shandong, Peoples R China.; [Yang, Bo; Zhang, Xiaoming; Zhao, Ming 更多
通讯作者：Zhao, MW;Zhao, MW;Zhao, Mingwen
通讯作者地址：[Zhao, MW]Shandong Univ, Sch Phys, Jinan 250100, Shandong, Peoples R China;[Zhao, MW]Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Shandong, 更多
来源：JOURNAL OF PHYSICS-CONDENSED MATTER
关键词：2D dirac materials; reflective symmetry; snub trihexagonal tiling; lattice; tight-binding model; first-principles calculations
摘要：The present models of the two-dimensional (2D) Dirac materials always have reflective symmetry, but the essentiality has never been proved. Here we present an exceptional case: a snub trihexagonal tiling (STT) lattice without reflective symmetry. We demonstrate the existence of Dirac cones in this reflection-symmetry-free lattice by using a single-orbital tight-binding (TB) Hamiltonian. The SST lattice is also topologically nontrivial, because the Dirac cone can be gapped by spin-orbit coupling (SOC) effect associated with robust gapless edge states. Using first-principles calculations, we predict a promising candidate 2D material, Be3C4 monolayer to realize this toy model. The Fermi velocities in this unique lattice are even higher than that in graphene. The stability and plausibility of the Be3C4 monolayer are verified by positive phonon modes, molecular dynamical simulations and mechanical criteria. This work eliminates the need for reflective symmetry in 2D Dirac materials, opening an avenue for designing new 2D Dirac materials.