Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahassee, Florida 32306, USA.
Phys Rev Lett. 2019 Nov 15;123(20):207601. doi: 10.1103/PhysRevLett.123.207601.
We propose a general framework for constructing a large set of nodal-point semimetals by tuning the number of linearly (d_{L}) and (at most) quadratically (d_{Q}) dispersing directions. By virtue of such a unifying scheme, we identify a new perturbative route to access various strongly interacting non-Dirac semimetals with d_{Q}>0. As a demonstrative example, we relate a two-dimensional anisotropic semimetal with d_{L}=d_{Q}=1, describing the topological transition between a Dirac semimetal and a normal insulator, and its three-dimensional counterparts with d_{L}=1, d_{Q}=2. We address the quantum critical phenomena and emergence of non-Fermi liquid states with unusual dynamical structures within the framework of an ε expansion, where ε=2-d_{Q}, when these systems reside at the brink of charge- or spin-density-wave orderings, or an s-wave pairing. Our results can be germane to two-dimensional uniaxially strained optical honeymcomb lattice, α-(BEDT-TTF){2}I{3}.
我们提出了一个构建大量节点型半金属的通用框架，通过调整线性（d_{L}）和（最多）二次（d_{Q}）色散方向的数量。通过这种统一的方案，我们确定了一种新的微扰途径，以获得各种具有 d_{Q}>0 的强相互作用的非狄拉克半金属。作为一个示范例子，我们将二维各向异性半金属与 d_{L}=d_{Q}=1 相关联，描述了狄拉克半金属和正常绝缘体之间的拓扑转变，以及其具有 d_{L}=1、d_{Q}=2 的三维对应物。我们在 ε 展开的框架内解决了量子临界现象和非费米液体状态的出现，其中 ε=2-d_{Q}，当这些系统处于电荷或自旋密度波有序或 s 波配对的边缘时。我们的结果可能与二维单轴应变光蜂窝晶格、α-(BEDT-TTF){2}I{3}有关。
