Observation of multiple types of topological fermions in PdBiSe

Abstract

Topological semimetals with different types of band crossings provide a rich platform to realize novel fermionic excitations, known as topological fermions. In particular, some fermionic excitations can be direct analogues of elementary particles in quantum field theory when both obey the same laws of physics in the low-energy limit. Examples include Dirac and Weyl fermions, whose solid-state realizations have provided new insights into long-sought phenomena in high-energy physics. Recently, theorists predicted new types of fermionic excitations in condensed-matter systems without any high-energy counterpart, and their existence is protected by crystalline symmetries. By studying the topology of the electronic structure in PdBiSe using density functional theory calculations and bulk-sensitive soft X-ray angle-resolved photoemission spectroscopy, we demonstrate a coexistence of four different types of topological fermions: Weyl, Rarita-Schwinger-Weyl, double class-II three-component, and charge-2 fourfold fermions. Our discovery provides a remarkable platform to realize multiple novel fermions in a single solid, charting the way forward to studies of their potentially exotic properties as well as their interplay.

References in corpus (10)

• Non-Abelian Anyons and Topological Quantum Computation
• Weyl semimetal phase in non-centrosymmetric transition metal monophosphides
• Multiple types of topological fermions in transition metal silicides
• 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
• Double-Weyl phonons in transition-metal monosilicides
• A precise method for visualizing dispersive features in image plots
• Possible Topological Superconducting Phases of MoS${}_2$
• Superconductivity in cubic noncentrosymmetric PdBiSe Crystal

Cited by in corpus (22)

• Topological Materials Discovery from Crystal Symmetry
• Twofold quadruple Weyl nodes in chiral cubic crystals
• Weyl phonons in chiral crystals
• Circular dichroism as a probe for topology in three-dimensional semimetals
• Transmission and conductance across junctions of isotropic and anisotropic three-dimensional semimetals
• Realization of Practical Eightfold Fermions and Fourfold van Hove Singularity in TaCo${}_2$Te${}_2$
• Persistent exchange splitting in a chiral helimagnet Cr1/3NbS2
• Band geometry from position-momentum duality at topological band crossings
• Signatures of topology in generic transport measurements for Rarita-Schwinger-Weyl semimetals
• Linear response in planar Hall and thermal Hall setups for Rarita-Schwinger-Weyl semimetals
• Andreev bound states in superconductor-barrier-superconductor junctions of Rarita-Schwinger-Weyl semimetals
• Protection of all nondefective twofold degeneracies by anti-unitary symmetries in non-Hermitian systems
• Reflections of topological properties in the planar-Hall response for semimetals carrying pseudospin-1 quantum numbers
• Strain-induced topological charge control in multifold fermion systems
• Charge order induced Dirac pockets in the nonsymmorphic crystal TaTe${}_4$
• Unpaired topological triply degenerate point for spin-tensor-momentum-coupled ultracold atoms
• Chiral phononic and electronic edge modes of EuPtSi
• Polar hairs of mixed-parity nodal superconductors in Rarita-Schwinger-Weyl metals
• Infrared fixed points of higher-spin fermions in topological semimetals
• Geometric semimetals and their simulation in synthetic matter
• Discovery of nodal-line superconductivity in chiral crystals
• Nature of Andreev bound states in Josephson junctions of triple-point semimetals