Unusual magnetotransport from Si-square nets in topological semimetal HfSiS

Abstract

Abstract:The class of topological semimetals comprises a large pool of compounds. Together they provide a wide platform to realize exotic quasiparticles for example Dirac, nodal line Dirac and Weyl fermions. In this letter, we report the Berry phase, Fermi surface topology and anisotropic magnetoresistance of HfSiS which has recently been predicted to be a nodal line semimetal. This compound contains large carrier density, higher than most of the known semimetals. Massive amplitudes of de Haas-van Alphen and Shubnikov-de Haas oscillations up to 20 K in 7 T assist us in witnessing nontrivial -Berry phase which is a consequence of topological Diractype dispersion of bands originating from the hybridization of px  py and dx2-y2 orbitals of squarenet plane of Si and Hf atoms, respectively. Furthermore, we establish the 3D Fermi-surface which consists of very asymmetric water caltrop-like electron and barley seed-like hole pockets which account for the anisotropic magnetoresistance in HfSiS.

Symmetry demanded topological nodal-line materials

“…MSiS [74,77,78,87,[131][132][133][134][135][136][137][138]: Zr(Hf)SiS is a tetragonal PbFCl-type compound with space group P4/nmm No. 129.…”

“…Extraordinary magneto-electronic transport phenomenon have been found in this material system [132][133][134][135][136]138]. The MR is large and positive for both materials, reaching 1.8 × 10 5 percent at 9T and 2K for ZrSiS without saturation [133][134][135]138].…”

“…The MR is large and positive for both materials, reaching 1.8 × 10 5 percent at 9T and 2K for ZrSiS without saturation [133][134][135]138]. The MR are both highly anisotropic and both compounds show a 'butterfly'-shaped angular MR, originating from the 2D and 3D Dirac pockets comprising Fermi surface [132,136,138]. In addition, ZrSiS also shows evidence of a topological phase transition with changing magnetic field angle [132].…”

“…Band structure without and with SOC Nodal line distribution without and with SOC ARPES [78] References [74,77,78,87,[131][132][133][134][135][136][137][138] very close to the E F , making it a good candidate system to study non-symmorphic line nodes [137]. Orthorhombic perovskite iridates [66,67,76,139,[144][145][146][147][148][149][150][151]: AIrO 3 , where A is an alkaline-earth metal, is a class of orthorhombic perovskite iridates in space group Pbnm No.…”

Strong correlation between mobility and magnetoresistance in Weyl and Dirac semimetals

“…Depending on their degeneracy, topological semimetals are further distinguished and classified into Weyl semimetals (WSM) and Dirac semimetals. The discovery of Weyl fermions in transition metal monopnictides [1][2][3][4][5][6] has facilitated the discovery of additional Dirac and Weyl semimetals in the various families of compounds [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27].…”