Interplay of magnetism and transport in HoBi

Abstract

We report the observation of an extreme magnetoresistance (XMR) in HoBi with a large magnetic moment from Ho f -electrons. Neutron scattering is used to determine the magnetic wave vectors across several metamagnetic (MM) transitions on the phase diagram of HoBi. Unlike other magnetic rare-earth monopnictides, the field dependence of resistivity in HoBi is non-monotonic and reveals clear signatures of every metamagnetic transition in the low-temperature and low-field regime, at T < 2 K and H < 2.3 T. The XMR appears at H > 2.3 T after all the metamagnetic transitions are complete and the system is spin-polarized by the external magnetic field. The existence of an onset field for XMR and the intimate connection between magnetism and transport in HoBi are unprecedented among the magnetic rare-earth monopnictides. Therefore, HoBi provides a unique opportunity to understand the electrical transport in magnetic XMR semimetals. PACS numbers: 71.20.Eh, 75.30.Kz, Non-magnetic rare-earth monopnictides with a chemical formula RX where R = Y or La and X = As, Sb, and Bi have attracted attention because they exhibit a non-saturating and extremely large magnetoresistance (XMR) [1][2][3][4][5][6][7][8][9][10][11][12][13]. A topological to trivial transition is reported in the LaX family, from LaBi to LaAs, with XMR being present on either side of the transition confirming that XMR originates from an electron-hole compensation instead of a topological band structure [6,14]. Recently, XMR has been reported in a few magnetic rareearth monopnictides including CeSb [15], NdSb [16,17], GdSb and GdBi [15,18,19] where f -electrons provide localized moments. In these magnetic semimetals, the itinerant d/p-electrons couple to the localized felectrons through the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction [20,21] giving rise to antiferromagnetic (AFM) order, field induced metamagnetic (MM) transitions, and rich magnetic phase diagrams [22][23][24][25][26][27][28]. Despite complex magnetization curves M (H) with multiple MM transitions, the magnetic monopnictides exhibit plain quadratic resistivity curves ρ(H) and an XMR behavior that is indistinguishable from their non-magnetic analogues in the low-temperature regime (T < 2 K) [15,17]. From LaSb/LaBi to CeSb, NdSb, and then GdSb/GdBi, the lanthanide becomes progressively more magnetic, but intriguingly no strong response of transport and XMR to magnetism has been observed so far.In search of such connection between magnetism and transport properties in a magnetic XMR material, we decided to study HoBi where Ho 3+ ions provide the largest * fazel.tafti@bc.edu total angular momentum J = L + S among the R 3+ ions. Through a combination of magnetization, neutron scattering, and transport experiments, we unveil an intimate relation between the electronic transport and the magnetism of HoBi unlike any previously studied magnetic RX system. Using neutron diffraction, we reveal a new ( 1 /6, 1 /6, 1 /6) ordered state at intermediate fields which strongly affects the resistivity behavior. T...

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

“…As presented above, high magnetic field drives the emergence of a particular case instead of the generally plain quadratic magnetoresistance curves expected in many other semimetals, which has been scarcely reported [18,29,36]. Therefore, an in-depth study on electronic structure of the ferromagnetic phase of HoBi could help to understand the origin of extreme magnetoresistance in rare earth monopnictide family.…”

“…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.…”

“…While, Fente et al reported that no hysteresis emerged during the evolution of magnetization as a function of field [40]. Beyond that complicated magnetic orders, recent studies have also drawn attention to the magnetotransport of HoBi [29]. Neutron diffraction reveals that the (1/6, 1/6, 1/6) ordered state could significantly affect the resistivity along [110] direction in the intermediate fields and the (0, 0, 0) polarized state drives the occurrence of extreme magnetoresistance [29].…”

“…Beyond that complicated magnetic orders, recent studies have also drawn attention to the magnetotransport of HoBi [29]. Neutron diffraction reveals that the (1/6, 1/6, 1/6) ordered state could significantly affect the resistivity along [110] direction in the intermediate fields and the (0, 0, 0) polarized state drives the occurrence of extreme magnetoresistance [29]. As reported, the magnetic phase diagram in the [001] direction is more complicated comparing to that along the [110] direction, indicating that different transport properties can be expected in the former magnetic states.Here, we aim to revaluate the magnetic transitions, and uncover the origin of extremely large magnetoresistance in HoBi single crystal.…”