Strain-induced spontaneous Hall effect in an epitaxial thin film of a Luttinger semimetal
Strain-induced spontaneous Hall effect in an epitaxial thin film of a Luttinger semimetal
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DOI：
10.1073/pnas.1819489116
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发表时间：
2019-04-30
影响因子：
11.1
通讯作者：
Nakatsuji, Satoru
中科院分区：
文献类型：
--
作者：
Ohtsuki, Takumi;Tian, Zhaoming;Nakatsuji, Satoru
由于拓扑学和相关性的结合，烧绿石铱酸盐提供了大量的新现象。其中，Pr_2Ir_2O_7作为一种Luttinger半金属，在布里渊区中心具有二次能带接触，表明其电子态的拓扑结构可以通过适当的晶格应变和外加磁场进行调节，因此受到了广泛的关注。在这里，我们报告说，我们的外延Pr2Ir2O7薄膜的固态外延生长表现出自发霍尔效应，持续到50 K，没有自发磁化在我们的实验精度。这表明，该系统打破了时间反演对称性的温度范围是太高的磁性是由于Pr 4f的时刻，必须有关的磁性顺序的铱5d电子。此外，我们的分析发现，手征异常诱导的负贡献的磁阻只有当磁场和电流相互平行。我们的结果表明，薄膜的应变部分形成磁性外尔半金属态。
Pyrochlore iridates have provided a plethora of novel phenomena owing to the combination of topology and correlation. Among them, much attention has been paid to Pr2Ir2O7, as it is known as a Luttinger semimetal characterized by quadratic band touching at the Brillouin zone center, suggesting that the topology of its electronic states can be tuned by a moderate lattice strain and external magnetic field. Here, we report that our epitaxial Pr2Ir2O7 thin films grown by solid-state epitaxy exhibit a spontaneous Hall effect that persists up to 50 K without having spontaneous magnetization within our experimental accuracy. This indicates that the system breaks the time reversal symmetry at a temperature scale that is too high for the magnetism to be due to Pr 4f moments and must be related to magnetic order of the iridium 5d electrons. Moreover, our analysis finds that the chiral anomaly induces the negative contribution to the magnetoresistance only when a magnetic field and the electric current are parallel to each other. Our results indicate that the strained part of the thin film forms a magnetic Weyl semimetal state.