论文标题
sragbi中II和IV类型Dirac Fermions的共存
Coexistence of Type-II and Type-IV Dirac Fermions in SrAgBi
论文作者
论文摘要
相对论的无质量Weyl和Dirac Fermions具有各向同性和线性分散关系，以维持庞加莱对称性，这是高能物理学中最基本的对称性。凝结物理学的情况受到较少的约束。只有某些庞加莱对称的亚组（3D晶格中存在的230个空间组）才需要尊重。然后，在固态系统中可能存在没有高能量类似物的自由效能激发。在这里，我们在Sragbi中发现了一种没有高能类似物的非线性Dirac Fermion，并将其命名为IV型Dirac Fermion。 IV型Dirac Fermion具有非线性分散关系，类似于II型Dirac Fermion，该型号具有电子口袋和孔口袋。还发现了IV型Dirac Fermion的有效模型。值得指出的是，这款新的迪拉克·费米恩（Dirac Fermion）附近有一个II型Dirac Fermion。因此，我们使用了两个模型来描述这两个狄拉克费米子的共存。还计算了这两个狄拉克点的拓扑表面状态。我们设想我们的发现将刺激研究人员研究IV类dirac fermions的新物理学，以及II型和IV型Dirac Fermions的相互作用。
Relativistic massless Weyl and Dirac fermions have isotropic and linear dispersion relations to maintain Poincaré symmetry, which is the most basic symmetry in high-energy physics. The situation in condensed matter physics is less constrained; only certain subgroups of Poincaré symmetry -- the 230 space groups that exist in 3D lattices -- need be respected. Then, the free fermionic excitations that have no high energy analogues could exist in solid state systems. Here, We discovered a type of nonlinear Dirac fermion without high-energy analogue in SrAgBi and named it type-IV Dirac fermion. The type-IV Dirac fermion has a nonlinear dispersion relationship and is similar to the type-II Dirac fermion, which has electron pocket and hole pocket. The effective model for the type-IV Dirac fermion is also found. It is worth pointing out that there is a type-II Dirac fermion near this new Dirac fermion. So we used two models to describe the coexistence of these two Dirac fermions. Topological surface states of these two Dirac points are also calculated. We envision that our findings will stimulate researchers to study novel physics of type-IV Dirac fermions, as well as the interplay of type-II and type-IV Dirac fermions.
