Arnab Pariari

Large nonsaturating magnetoresistance and signature of nondegenerate Dirac nodes in ZrSiS

Significance Topological semimetals provide the opportunity to explore the fundamental physics of relativistic particles and offer the possibility of technological applications. However, finding robust systems with a sufficiently large range of linearly dispersing bands remains elusive. Recently discovered Dirac semimetal ZrSiS hosts multiple Dirac cones with the largest reported energy range of linear band dispersion (∼2 eV). In this work, we report transport measurements on ZrSiS, exploring extreme and anisotropic magnetoresistance with distinct quantum oscillations, enabling us to quantitatively analyze the Fermi surface properties. We have also observed the unique signature of chiral anomaly in longitudinal magnetoresistance. Our work comprehensively confirms the recent theoretical and angle-resolved photoemission spectroscopy results on ZrSiS and suggests a large family of materials as potential topological semimetals. Whereas the discovery of Dirac- and Weyl-type excitations in electronic systems is a major breakthrough in recent condensed matter physics, finding appropriate materials for fundamental physics and technological applications is an experimental challenge. In all of the reported materials, linear dispersion survives only up to a few hundred millielectronvolts from the Dirac or Weyl nodes. On the other hand, real materials are subject to uncontrolled doping during preparation and thermal effect near room temperature can hinder the rich physics. In ZrSiS, angle-resolved photoemission spectroscopy measurements have shown an unusually robust linear dispersion (up to ∼2 eV) with multiple nondegenerate Dirac nodes. In this context, we present the magnetotransport study on ZrSiS crystal, which represents a large family of materials (WHM with W = Zr, Hf; H = Si, Ge, Sn; M = O, S, Se, Te) with identical band topology. Along with extremely large and nonsaturating magnetoresistance (MR), ∼1.4 × 105% at 2 K and 9 T, it shows strong anisotropy, depending on the direction of the magnetic field. Quantum oscillation and Hall effect measurements have revealed large hole and small electron Fermi pockets. A nontrivial π Berry phase confirms the Dirac fermionic nature for both types of charge carriers. The long-sought relativistic phenomenon of massless Dirac fermions, known as the Adler–Bell–Jackiw chiral anomaly, has also been observed.

Probing the Fermi surface of three-dimensional Dirac semimetalCd3As2through the de Haas–van Alphen technique

We have observed Shubnikov-de Haas and de Haas-van Alphen effect in the single crystals of three dimensional Dirac semimetal Cd

Coexistence of topological Dirac fermions in the surface and three-dimensional Dirac cone state in the bulk of ZrTe

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As

single crystal

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Magnetotransport properties and evidence of a topological insulating state in LaSbTe

upto 50 K, traceable at field as low as 2 T and 1 T, respectively. The values of Fermi wave vector, Fermi velocity, and effective cyclotron mass of charge carrier, calculated from both the techniques, are close to each other and match well with the earlier reports. However, the de Haas-van Alphen effect clearly reflects the existence of two different Fermi surface cross-sections along certain direction and a non-trivial Berrys phase which is the signature of 3D Dirac Fermion in Cd

Magneto-transport properties of proposed triply degenerate topological semimetal Pd3Bi2S2

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Prominent metallic surface conduction and the singular magnetic response of topological Dirac fermion in three-dimensional topological insulator Bi 1.5 Sb 0.5 Te 1.7 Se 1.3

As

Anisotropic transverse magnetoresistance and Fermi surface in TaSb 2

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Planar Hall effect in type II Dirac semimetal VAl

.