Probing the Origin of Extreme Magnetoresistance in Pr/Sm Mono-Antimonides/Bismuthides

TL;DR

This study combines spectroscopy and transport measurements to investigate the origin of extreme magnetoresistance in Pr/Sm mono-antimonides/bismuthides, finding electron-hole compensation and band structure features as key factors.

Contribution

It demonstrates that the extreme magnetoresistance arises from electron-hole compensation and not topological surface states, providing a comprehensive understanding of the phenomenon.

Findings

Electron-hole compensation explains the magnetoresistance.

Bulk band structure shows no temperature dependence from 10K to 150K.

Carrier mobility increases at low temperatures, suppressing magnetoresistance.

Abstract

Combining angle-resolved photoemission spectroscopy and magneto-transport measurements, we systematically investigated the possible origin of the extreme magnetoresistance in Pr/Sm mono-antimonides/bismuthides (PrSb, SmSb, PrBi, SmBi). Our photoemission measurements reveal that the bulk band inversion and surface states are absent (present) in Pr/Sm antimonides (bismuthides), implying that topological surface states are unlikely to play an important role for the observed extreme magnetoresistance. We found that the electron-hole compensation is well satisfied in all these compounds and the bulk band structure exhibits no obvious temperature dependence from 10 K up to 150 K. Simultaneous fittings of the magnetoresistance and Hall coefficient reveal that the carrier mobility is dramatically enhanced at low temperature, which naturally explains the suppression of extreme magnetoresistance at high temperatures. Our results therefore show that the extreme magnetoresistance in these compounds can be well accounted for by the two-band model with good electron-hole compensation. Finally, we found that both PrSb and SmSb exhibit highly linear bulk bands near the X point and lie close to the transition point between a topologically trivial and nontrivial phase, which might be relevant for the observed anomalous quantum oscillations.