Gigantic magnetoresistance in ultrahigh mobility NbP: A candidate topological Weyl semimetal
Researchers from the Max Planck Institute for Chemical Physics of Solids in Dresden (Germany) have synthesized high-quality single crystals of NbP and measured their transport properties in continuous magnetic fields up to 30 T at HFML-EMFL Nijmgen and in pulsed magnetic fields up to 62 T at HLD-EMFL Dresden.
The electric resistance increases linearly with magnetic field by a factor of up to 8.1×104 (at B = 62 T and T = 1.5 K) without any signs of saturation. This value is comparable to the spectacularly large non-saturating magnetoresistance recently observed in other materials such as WTe2 and TaAs. Even at room temperature the magnetoresistance is still as high as 250% in a magnetic field of 9 T and NbP might therefore have a promising application perspective for future magnetoresistive devices.
Additionally, the NbP samples investigated show an ultrahigh mobility of 5×106 cm2V-1s-1 leading to the observation of quantum oscillations in the low-temperature magnetoresistance (the so-called Shubnikov–de Haas effect). These oscillations are consistent with the presence of small pockets in the Fermi surface near the Weyl points in the bandstructure. Therefore, NbP can be regarded as a material with properties combining the topological electron phases of a Weyl semimetal with those of a conventional semimetal.
Chandra Shekhar, Ajaya K. Nayak, Yan Sun, Marcus Schmidt, Michael Nicklas, Inge Leermakers, Uli Zeitler, Yurii Skourski, Jochen Wosnitza, Zhongkai Liu, Yulin Chen, Walter Schnelle, Horst Borrmann, Yuri Grin, Claudia Felser& Binghai Yan, Extremely large magnetoresistance and ultrahigh mobility in the topological Weyl semimetal candidate NbP, Nature Physics 11, 645 (2015).
With 300 kilometres per second to new electronics, Research News Max Planck Institute for Chemical Physics of Solids, 22 June 2015
Relative magnetoresistance of a NbP single crystal measured in magnetic fields up to 30 T at HFML-EMFL Nijmegen. The sample displays and extraordinarily large non-saturating magnetoresistance with low-temperature Shubnikov de Haas oscillations superimposed on it. The inset shows the schematic semi-metallic band structure of NbP with a hole pocket (light blue) from a conventional quadratic band and an electron pocket (light green) from a Weyl-type band with a linear dispersion. The blue line indicates the position of the Fermi energy EF.