Singha Ratnadwip, Dalgaard Kirstine J, Marchenko Dmitry, Krivenkov Maxim, Rienks Emile D L, Jovanovic Milena, Teicher Samuel M L, Hu Jiayi, Salters Tyger H, Lin Jingjing, Varykhalov Andrei, Ong N Phuan, Schoop Leslie M
Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Straße 15, 12489 Berlin, Germany.
Sci Adv. 2023 Oct 13;9(41):eadh0145. doi: 10.1126/sciadv.adh0145.
Colossal negative magnetoresistance is a well-known phenomenon, notably observed in hole-doped ferromagnetic manganites. It remains a major research topic due to its potential in technological applications. In contrast, topological semimetals show large but positive magnetoresistance, originated from the high-mobility charge carriers. Here, we show that in the highly electron-doped region, the Dirac semimetal CeSbTe demonstrates similar properties as the manganites. CeSbTe hosts multiple charge density wave modulation vectors and has a complex magnetic phase diagram. We confirm that this compound is an antiferromagnetic Dirac semimetal. Despite having a metallic Fermi surface, the electronic transport properties are semiconductor-like and deviate from known theoretical models. An external magnetic field induces a semiconductor metal-like transition, which results in a colossal negative magnetoresistance. Moreover, signatures of the coupling between the charge density wave and a spin modulation are observed in resistivity. This spin modulation also produces a giant anomalous Hall response.
巨负磁阻是一种众所周知的现象，尤其在空穴掺杂的铁磁锰氧化物中被观察到。由于其在技术应用中的潜力，它仍然是一个主要的研究课题。相比之下，拓扑半金属表现出大但为正的磁阻，这源于高迁移率的电荷载流子。在此，我们表明在高电子掺杂区域，狄拉克半金属CeSbTe表现出与锰氧化物类似的性质。CeSbTe具有多个电荷密度波调制矢量且具有复杂的磁相图。我们证实该化合物是一种反铁磁狄拉克半金属。尽管具有金属费米面，但其电子输运性质类似半导体且偏离已知的理论模型。外部磁场会诱导半导体 - 金属样转变，这会导致巨负磁阻。此外，在电阻率中观察到电荷密度波与自旋调制之间耦合的特征。这种自旋调制还产生巨大的反常霍尔响应。
