Singular angular magnetoresistance in a magnetic nodal semimetal
Singular angular magnetoresistance in a magnetic nodal semimetal
复制标题
DOI：
10.1126/science.aat0348
复制
发表时间：
2019-06
期刊：
影响因子：
56.9
通讯作者：
Takehito Suzuki;L. Savary;L. Savary;L. Savary;Jianpeng Liu;Jianpeng Liu;J. Lynn;L. Balents;
中科院分区：
文献类型：
--
作者：
Takehito Suzuki;L. Savary;L. Savary;L. Savary;Jianpeng Liu;Jianpeng Liu;J. Lynn;L. Balents;
注意角度材料的真实的和动量空间性质之间的相互作用会导致奇异现象。Suzuki等人研究了在磁场存在下铈铝锗中的电输运，这是一种外尔半金属，也具有磁性（参见Hassinger和Meng的观点）。当他们改变外加磁场的方向时，他们注意到电阻率的尖峰急剧集中在材料的高对称轴周围。尖峰是费米面（“生活”在动量空间中）在磁畴壁两侧的微小重叠的结果，磁畴壁发生在真实的空间中。这种极端的角度灵敏度在实际应用中可能是有用的。《科学》杂志，本期第377页;另见第324页，传输测量表明CeAlGe对外加磁场的角度极为敏感。关联电子系统的输运系数通常用于映射具有不同对称性的隐藏相位。在这里，我们报告了在磁性Weyl半金属铈铝锗（CeAlGe）系统的自发对称性破缺的奇异角磁阻（SAMR）的形式的运输签名。这种超过每弧度1000%的角响应被沿着高对称轴限制，半峰全宽达到小于1°，并且通过硅对锗的等电子部分替代是可调谐的。SAMR现象的理论解释为可控的高电阻畴壁的结果，所产生的强烈耦合到一个近节的电子结构的磁点群对称性的破坏。本研究借由晶格对称性与位点对称性，指出高角度感度工程磁性材料的成分。
Mind the angle Interplay between real- and momentum-space properties of materials can lead to exotic phenomena. Suzuki et al. studied electrical transport in the presence of a magnetic field in cerium-aluminum-germanium, a Weyl semimetal that also harbors magnetism (see the Perspective by Hassinger and Meng). As they varied the orientation of the applied field, they noticed spikes of resistivity sharply centered around the high symmetry axes of the material. The spikes were a consequence of the small overlap of Fermi surfaces—which “live” in momentum space—on either side of magnetic domain walls, which occur in real space. This extreme angular sensitivity may be useful in practical applications. Science, this issue p. 377; see also p. 324 Transport measurements show extreme sensitivity to the angle of the applied magnetic field in CeAlGe. Transport coefficients of correlated electron systems are often useful for mapping hidden phases with distinct symmetries. Here we report a transport signature of spontaneous symmetry breaking in the magnetic Weyl semimetal cerium-aluminum-germanium (CeAlGe) system in the form of singular angular magnetoresistance (SAMR). This angular response exceeding 1000% per radian is confined along the high-symmetry axes with a full width at half maximum reaching less than 1° and is tunable via isoelectronic partial substitution of silicon for germanium. The SAMR phenomena is explained theoretically as a consequence of controllable high-resistance domain walls, arising from the breaking of magnetic point group symmetry strongly coupled to a nearly nodal electronic structure. This study indicates ingredients for engineering magnetic materials with high angular sensitivity by lattice and site symmetries.