title: Coexistence of topological Dirac fermions on the surface and three-dimensional Dirac cone state in the bulk of ZrTe5single crystal.
abstract: Although, the long-standing debate on the resistivity anomaly in ZrTe5somewhat comes to an end, the exact topological nature of the electronic band structure remains elusive till today. Theoretical calculations predicted that bulk ZrTe5to be either a weak or a strong three-dimensional (3D) topological insulator. However, the angle resolved photoemission spectroscopy and transport measurements clearly demonstrate 3D Dirac cone state with a small mass gap between the valence band and conduction band in the bulk. From the magnetization and magneto-transport measurements on ZrTe5single crystal, we have detected both the signature of helical spin texture from topological surface state and chiral anomaly associated with the 3D Dirac cone state in the bulk. This implies that ZrTe5hosts a novel electronic phase of material, having massless Dirac fermionic excitation in its bulk gap state, unlike earlier reported 3D topological insulators. Apart from the band topology, it is also apparent from the resistivity and Hall measurements that the anomalous peak in the resistivity can be shifted to a much lower temperature (T < 2 K) by controlling impurity and defects.
authors.affiliation: Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Calcutta 700 064, India.
authors.forename: Arnab
authors.initials: A
authors.lastname: Pariari
authors.affiliation: Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Calcutta 700 064, India.
authors.forename: Prabhat
authors.initials: P
authors.lastname: Mandal
mesh_terms: D055598:Chemical Phenomena; D003460:Crystallization; D004583:Electrons; D060526:Magnetic Fields; D010316:Particle Size; D013499:Surface Properties; D013696:Temperature; D015040:Zirconium / Q000737:chemistry*
chemical_list: D015040:Zirconium