Kramers-Weyl fermions in the chiral charge density wave material (TaSe${}_4$)${}_2$I

Abstract

The quasi-one-dimensional chiral charge density wave (CDW) material (TaSe${}_4$)${}_2$I has been recently predicted to host Kramers-Weyl (KW) fermions which should exist in the vicinity of high symmetry points in the Brillouin zone in chiral materials with strong spin-orbit coupling. However, direct spectroscopic evidence of KW fermions is limited. Here we use helicity-dependent laser-based angle resolved photoemission spectroscopy (ARPES) in conjunction with tight-binding and first-principles calculations to identify KW fermions in (TaSe${}_4$)${}_2$I. We find that topological and symmetry considerations place distinct constraints on the (pseudo-) spin texture and the observed spectra around a KW node. We further reveal an interplay between the spin texture around the chiral KW node and the onset of CDW order in (TaSe${}_4$)${}_2$I. Our findings highlight the unique topological nature of (TaSe${}_4$)${}_2$I and provide a pathway for identifying KW fermions in other chiral materials.

References in corpus (41)

• Berry Phase Effects on Electronic Properties
• Topological Insulators in Three Dimensions
• Weyl and Dirac Semimetals in Three Dimensional Solids
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Discovery of a Three-dimensional Topological Dirac Semimetal, Na3Bi
• High-throughput electronic band structure calculations: challenges and tools
• Topological quantum chemistry
• Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals
• The (High Quality) Topological Materials In The World
• Observation of Weyl nodes in TaAs
• Discovery of a Weyl Fermion semimetal state in NbAs
• Catalogue of Topological Electronic Materials
• Hexagonal Warping Effects in the Surface States of Topological Insulator Bi${}_2$Te${}_3$
• Quantized circular photogalvanic effect in Weyl semimetals
• Berry phase, hyperorbits, and the Hofstadter spectrum: semiclassical dynamics in magnetic Bloch bands
• Electronic structure of quantum materials studied by angle-resolved photoemission spectroscopy
• Topological quantum properties of chiral crystals
• Large Fermi Arcs in Unconventional Weyl Semimetal RhSi
• Discovery of topological chiral crystals with helicoid arc states
• New classes of chiral topological nodes with non-contractible surface Fermi arcs in CoSi
• Chiral Topological Semimetal with Multifold Band Crossings and Long Fermi arcs
• Chiral anomaly, Charge Density Waves, and Axion Strings from Weyl Semimetals
• Evidence for an axionic charge density wave in the Weyl semimetal (TaSe4)2I
• Observation of a warped helical spin-texture in Bi${}_2$Se${}_3$ from circular dichroism angle-resolved photoemission spectroscopy
• Chiral Optical Response of Multifold Fermions
• Efficient Topological Materials Discovery Using Symmetry Indicators
• Giant topological longitudinal circular photo-galvanic effect in the chiral multifold semimetal CoSi
• Radial spin texture in elemental tellurium with chiral crystal structure
• In-Plane Orbital Texture Switch at the Dirac Point in the Topological Insulator Bi2Se3
• Detecting Chiral Orbital Angular Momentum by Circular Dichroism ARPES
• Type-III Weyl Semimetals: (TaSe4)2I
• Spin Polarization of Photoelectrons from Topological Insulators
• Linear and nonlinear optical responses in the chiral multifold semimetal RhSi
• Observation of warping effects in the band and angular momentum structures of topological insulator Bi2Te3
• Ultraquantum magnetoresistance in single-crystalline $\beta$-Ag${}_2$Se
• Ultraquantum magnetoresistance in Kramers Weyl semimetal candidate $\beta$-Ag2Se
• Electronic Instability in a Zero-Gap Semiconductor: the Charge-Density Wave in (TaSe4)2I
• Determine the chirality of Weyl fermions from the circular dichroism spectra of time-dependent ARPES
• The momentum and photon energy dependence of the circular dichroic photoemission in the bulk Rashba semiconductors BiTeX (X = I, Br, Cl)
• Tight-binding approach to understand photoelectron intensity from graphene for circularly polarized light
• Pseudo-Spin, Real-Spin and Spin Polarization of Photo-emitted Electrons

Cited by in corpus (1)

• Absence of in-gap modes in charge density wave edge dislocations of the Weyl semimetal (TaSe${}_4$)${}_2$I