Electronic transport properties of topological ferroelectric Ni2P

Recently, topological ferroelectricity was discovered in metallic nickel phosphide, Ni2P. First-principles calculations of the electronic band structure suggest that its bulk conductivity originates from a three-dimensional Ni-Ni bonding network [1]. Here we report detailed magnetotransport studies of Ni2P. Single crystals of Ni2P were grown by two different routes: using self-flux and using bismuth flux, which resulted in a notable difference in electronic properties, apparently due to stoichiometry variation. Regardless of these differences, in crystals of both types, we observed strong deviations from the quadratic magnetic field -dependent magnetoresistance and a significantly nonlinear Hall effect, similar to the semimetallic monophosphides, NbP and TaP [2]. The possible origin of these results is discussed.

[1] X. K. Wei et al., Discovery of Real-Space Topological Ferroelectricity in Metallic Transition Metal Phosphides, Adv. Mater. 32, 46 (2020).

[2] I.A. Leahy et al., Nonsaturating large magnetoresistance in semimetals, PNAS 115, 42 (2018).

This research is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Science and Engineering Division through the Ames Laboratory. The Ames National Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358.