Distinct multiple fermionic states in a single topological metal

M. Mofazzel Hosen; Klauss Dimitri; Ashis K. Nandy; Alex Aperis; Raman Sankar; Gyanendra Dhakal; Pablo Maldonado; Firoza Kabir; Christopher Sims; Fangcheng Chou; Dariusz Kaczorowski; Tomasz Durakiewicz; Peter M. Oppeneer; Madhab Neupane

doi:10.1038/s41467-018-05233-1

arXiv · 1711.07390

Distinct multiple fermionic states in a single topological metal

M. Mofazzel Hosen·Klauss Dimitri·Ashis K. Nandy·Alex Aperis·Raman Sankar·Gyanendra Dhakal·Pablo Maldonado·Firoza Kabir·Christopher Sims·Fangcheng Chou·Dariusz Kaczorowski·Tomasz Durakiewicz·Peter M. Oppeneer·Madhab Neupane

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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.

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M. Mofazzel Hosen, Klauss Dimitri, Ashis K. Nandy, Alex Aperis, Raman Sankar, Gyanendra Dhakal, Pablo Maldonado, Firoza Kabir, Christopher Sims, Fangcheng Chou, Dariusz Kaczorowski, Tomasz Durakiewicz, Peter M. Oppeneer, Madhab Neupane. 2017-11-20. Distinct multiple fermionic states in a single topological metal. https://doi.org/10.1038/s41467-018-05233-1

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