Distinct multiple fermionic states in a single topological metal

Abstract

Among the quantum materials that gained interest recently are the topological Dirac/Weyl semimetals, where conduction and valence bands touch at points in reciprocal (k)-space, and the Dirac nodal-line semimetals, where these bands touch along a line or a loop in k-space. However, the coexistence of multiple fermion phases in one and the same material has not been verified yet. Using angle-resolved photoemission spectroscopy (ARPES) and first-principles electronic structure calculations, we systematically study the metallic topological quantum material, Hf2Te2P. Our investigations discover various properties that are rare and never observed in a single Dirac material. We observe the coexistence of both weak and strong topological surface states in the same material and interestingly, at the same momentum position. An one-dimensional Dirac crossing{the Dirac-node arc-along a high-symmetry direction is revealed by our first-principles calculations and confirmed by our ARPES measurements. This novel state is associated with the surface bands of a weak topological insulator protected by in-plane time-reversal invariance. Ternary compound Hf2Te2P thus emerges as an intriguing platform to study the coexistence and competition of multi-fermionic states in one material.

8 pages, 5 figures

References in corpus (11)

• Topological Insulators with Inversion Symmetry
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Classification of stable three-dimensional Dirac semimetals with nontrivial topology
• Observation of Topological Nodal Fermion Semimetal Phase in ZrSiS
• Discovery of Dirac Node Arcs in PtSn4
• Unexpected Dirac-Node Arc in the Topological Line-Node Semimetal HfSiS
• Tunability of the topological nodal-line semimetal phase in ZrSiX-type materials
• Molecular Beam Epitaxy of thin HfTe2 semimetal films
• Observation of the spin-polarized surface state in a noncentrosymmetric superconductor BiPd
• Observation of Gapless Dirac Surface States in ZrGeTe
• One-dimensional Dirac electrons on the surface of weak topological insulators

Cited by in corpus (10)

• Observation of topological nodal-line fermionic phase in GdSbTe
• Temperature Dependent Electronic Structure in a Higher Order Topological Insulator Candidate EuIn${}_2$As${}_2$
• Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP
• Termination Dependent Topological Surface States in Nodal Loop Semimetal HfP2
• Tailoring phase transition from topological superconductor to trivial superconductor induced by magnetic textures of a spin-chain on a $p$-wave superconductor
• Observation of anisotropic Dirac cones in the topological material Ti2Te2P
• Topological surface states above the Fermi energy in ${\text{Hf}}_2{\text{Te}}_2\text{P}$
• Experimental observation and spin texture of Dirac node arcs in tetradymite topological metals
• Vector Chirality $\kappa$ Driven Topological Phase Transition and the Associated Anomalous Hall Conductivity Tuning in a Non-Collinear Antiferromagnet
• Strong and Weak Three-Dimensional Topological Insulators Probed by Surface Science Methods