Large negative magnetoresistance in the antiferromagnet BaMn2Bi2
Large negative magnetoresistance in the antiferromagnet BaMn2Bi2
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DOI：
10.1103/physrevb.103.125108
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发表时间：
2021-03
影响因子：
3.7
通讯作者：
T. Ogasawara;K. Huynh;Time Tahara;T. Kida;M. Hagiwara;D. Arčon;M. Kimata;S. Y. Matsushita;Kazuma Nagata;K. Tanigaki
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文献类型：
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作者：
T. Ogasawara;K. Huynh;Time Tahara;T. Kida;M. Hagiwara;D. Arčon;M. Kimata;S. Y. Matsushita;Kazuma Nagata;K. Tanigaki
当磁场垂直于亚晶格磁化方向施加时，在反铁磁体${\mathrm{BaMn}}_{2}{\mathrm{Bi}}_{2}$的绝缘态中观察到非常大的负磁阻（LNMR）。高垂直磁场最终抑制了绝缘行为，并使${\mathrm{BaMn}}_{2}{\mathrm{Bi}}_{2}$重新进入金属态。这种效应似乎与任何场诱导的磁相变无关，因为在高于$2\mathrm{K}$的温度下，磁化率和比热的测量未发现任何作为磁场函数的异常。LNMR在面内电流和面外电流两种设置中均出现，并且霍尔效应表明其起源在于空穴型载流子的传导过程对亚晶格磁化的微小场诱导倾斜的极端敏感性。因此，LNMR诱导的金属态可能与垂直磁场破坏反铁磁宇称 - 时间对称性和/或${\mathrm{BaMn}}_{2}{\mathrm{Bi}}_{2}$复杂的多轨道电子结构有关。
A very large negative magnetoresistance (LNMR) is observed in the insulating regime of the antiferromagnet ${\mathrm{BaMn}}_{2}{\mathrm{Bi}}_{2}$ when a magnetic field is applied perpendicular to the direction of the sublattice magnetization. A high perpendicular magnetic field eventually suppresses the insulating behavior and allows ${\mathrm{BaMn}}_{2}{\mathrm{Bi}}_{2}$ to reenter a metallic state. This effect is seemingly unrelated to any field-induced magnetic phase transition, as measurements of magnetic susceptibility and specific heat did not find any anomaly as a function of magnetic fields at temperatures above $2\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. The LNMR appears in both current-in-plane and current-out-of-plane settings, and Hall effects suggest that its origin lies in an extreme sensitivity of conduction processes of holelike carriers to the infinitesimal field-induced canting of the sublattice magnetization. The LNMR-induced metallic state may thus be associated with the breaking of the antiferromagnetic parity-time symmetry by perpendicular magnetic fields and/or the intricate multiorbital electronic structure of ${\mathrm{BaMn}}_{2}{\mathrm{Bi}}_{2}$.