Hourglass Weyl loops in two dimensions: Theory and material realization in monolayer GaTeI family

Abstract

Nodal loops in two-dimensional (2D) systems are typically vulnerable against spin-orbit coupling (SOC). Here, we explore 2D systems with a type of doubly degenerate nodal loops that are robust under SOC and feature an hourglass type dispersion. We present symmetry conditions for realizing such hourglass Weyl loops, which involve nonsymmorphic lattice symmetries. Depending on the symmetry, the loops may exhibit different patterns in the Brillouin zone. Based on first-principles calculations, we identify the monolayer GaTeI-family materials as a realistic material platform to realize such loops. These materials host a single hourglass Weyl loop circling around a high-symmetry point. Interestingly, there is also a spin-orbit Dirac point enabled by an additional screw axis. We show that the hourglass Weyl loop and the Dirac point are robust under a variety of applied strains. By breaking the screw axis, the Dirac point can be transformed into a second Weyl loop. Furthermore, by breaking the glide mirror, the hourglass Weyl loop and the spin-orbit Dirac point can both be transformed into a pair of spin-orbit Weyl points. Our work offers guidance and realistic material candidates for exploring fascinating physics of several novel 2D emergent fermions.

arXiv comment11 pages, 10 figures

References in corpus (46)

• Electronic Structure of Pyrochlore Iridates: From Topological Dirac Metal to Mott Insulator
• Van der Waals density functionals applied to solids
• Weyl and Dirac Semimetals in Three Dimensional Solids
• Observation of tightly bound trions in monolayer MoS2
• Classification of topological quantum matter with symmetries
• Dirac semimetal and topological phase transitions in A3Bi (A=Na, K, Rb)
• Topological Materials: Weyl Semimetals
• Dirac semimetal in three dimensions
• Three Dimensional Dirac Semimetal and Quantum Transports in Cd3As2
• Colloquium: Topological Band Theory
• Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals
• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• The interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons
• Dirac Line Nodes in Inversion Symmetric Crystals
• Topological Nodal Line Semimetal and Dirac Semimetal State in Antiperovskite Cu${}_3$PdN
• Topological Node-Line Semimetal in Three Dimensional Graphene Networks
• Topological nodal line semimetals
• Dirac Semimetals in Two Dimensions
• Topological Semimetals
• Nodal-chain metals
• Hourglass Fermions
• Ultrafast Optical Excitation of a Persistent Surface-State Population in the Topological Insulator Bi2Se3
• Spin-orbit-free Weyl-loop and Weyl-point semimetals in a stable three-dimensional carbon allotrope
• Nodal surface semimetals: Theory and material realization
• Line of Dirac Nodes in Hyper-Honeycomb Lattices
• Dirac and Weyl Superconductors in Three Dimensions
• Discovery of two-dimensional Dirac nodal line fermions in monolayer Cu2Si
• Node-Surface and Node-Line Fermions From Nonsymmorphic Lattice Symmetries
• Towards Three-Dimensional Weyl-SurfaceSemimetals in Graphene Networks
• Type-II nodal loops: theory and material realization
• Nonsymmorphic-symmetry-protected hourglass Dirac loop, nodal line, and Dirac point in bulk and monolayer $X_3$SiTe${}_6$ ($X=$ Ta, Nb)
• Experimental Discovery of the First Nonsymmorphic Topological Insulator KHgSb
• Hourglass Dirac Chain Metal in Rhenium Dioxide
• Artificial gravity field, astrophysical analogues, and topological phase transitions in strained topological semimetals
• Nodal Loop and Nodal Surface States in Ti3Al Family Materials
• Dirac and Weyl Materials: Fundamental Aspects and Some Spintronics Applications
• Atomic Scale Visualization of Quantum Interference on a Weyl Semimetal Surface by Scanning Tunneling Microscopy/Spectroscopy
• Quadratic and Cubic Nodal Lines Stabilized by Crystalline Symmetry
• Two-dimensional honeycomb borophene oxide: Strong anisotropy and nodal loop transformation
• Hybrid Nodal Loop Metal: Unconventional Magnetoresponse and Material Realization
• Electronic, Dielectric, and Plasmonic Properties of Two-Dimensional Electride Materials X${}_2$N (X=Ca, Sr): A First-Principles Study
• Two-dimensional Spin-Orbit Dirac Point in Monolayer HfGeTe
• Controllable two-dimensional robust multiferroic GaTeCl monolayer with giant ferroelectricity and superior multifunctions
• Weyl-loop half metal in Li${}_3$(FeO${}_3$)${}_2$
• Hexagonal supertetrahedral boron: A topological metal with multiple spin-orbit-free emergent fermions
• Topological Nonsymmorphic Ribbons out of Symmorphic Bulk

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