Topological semimetal state and field-induced Fermi surface reconstruction in the antiferromagnetic monopnictide NdSb

Abstract

We report the experimental realization of Dirac semimetal state in NdSb, a material with antiferromagnetic ground state. The occurrence of topological semimetal state has been well supported by our band structure calculations and the experimental observation of chiral anomaly induced negative magnetoresistance. A field-induced Fermi surface reconstruction is observed, in response to the change of spin polarization. The observation of topological semimetal state in a magnetic material provides an opportunity to investigate the magneto-topological phenomena.

Multiple metamagnetism, extreme magnetoresistance and nontrivial topological electronic structures in the magnetic semimetal candidate holmium monobismuthide

“…Such deviations have been observed in other materials hosting extreme magnetoresistance as well, like PtSn 4 , WTe 2 , and some rare earth manopnictides, e.g. LaSb/Bi, NdSb, YSb/Bi, LuSb/Bi [21,25,26,28,46,49,50]. Traditionally, the extremely large magnetoresistance is discussed in the framework of two-band model, which can be expressed as r = where r xx is the longitudinal resistivity, e is the electron charge, n is the carrier density, u is the mobility, and the subscripts e and h denote the electron-type and hole-type carriers, respectively [28].…”

“…Thanks to the advances in crystal growth techniques, the rare earth monopnictides with partially filled f shells provide possibilities to study the exotic properties. For example, chiral-anomaly-related negative magnetoresistance observed in NdSb indicates that this antiferromagnetic compound is a Dirac semimetal [26]. Nontrivial Berry phase obtained in the ferromagnetic state of HoSb indirectly reveals its topological nature as well [36].…”

“…The extreme magnetoresistance has been widely reported in the classic elemental semimetal Bi, topological semimetals WTe 2 , Cd 3 As 2 , TaPn (Pn = As, Sb) family, pyrite-type PtBi 2 , RPtBi (R=Nd, Gd), RPn (R=rare earth; Pn = Sb, Bi) and so on . Ever since the unprecedentedly large magnetoresistance is revealed in LaSb, the research enthusiasm on rare earth monopnictides RPn (R=rare earth, Pn = Sb, Bi) is inspired [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. The family has been widely studied in the 1980-90s for its heavy-fermion nature [31].…”

“…Intriguingly, the recent calculations predict that LaPn (Pn = N, P, As, Sb, and Bi) could be a topological prototype material with band inversion at X point of the bulk fcc Brillouin zone [32]. Afterwards, further investigation on this family has been systematically performed [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. It is found that some members of this family have topologically nontrivial band structures.…”

“…Actually, materials with spin degree of freedom are involved in the initial proposals of topological semimetals, where the spin degeneracy of bands can be lifted by breaking the time-reversal symmetry [35]. For absence of high-quality samples, it is hard to observe the topological states in magnetic semimetals [26]. Thanks to the advances in crystal growth techniques, the rare earth monopnictides with partially filled f shells provide possibilities to study the exotic properties.…”