<br>费米能级调谐 Kagome 反铁磁体中室温下的大反常霍尔效应,Advanced Functional Materials

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费米能级调谐 Kagome 反铁磁体中室温下的大反常霍尔效应
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2024-02-27 , DOI: 10.1002/adfm.202316588
Linxuan Song ₁ , Feng Zhou _{1,

2} , Hang Li _{1,

2} , Bei Ding ₁ , Xue Li _{1,

3} , Xuekui Xi ₁ , Yuan Yao ₁ , Yong‐Chang Lau _{1,

3} , Wenhong Wang _{1,

2}

Affiliation

最近在反铁磁体中发现的惊人的大反常霍尔效应（AHE）由于其在自旋电子器件中的应用前景而引起了广泛关注。然而，这种含有 AHE 的反铁磁材料在自然界中很少见。在此，证明了Mn _2.4 Ga，一种费米能级调谐的kagome反铁磁体，具有约150 Ω ⁻¹ cm ⁻¹ 的大反常霍尔电导率在室温下，超过了迄今为止在两种出色的 kagome 反铁磁体 Mn ₃ Sn 中观察到的通常高值（即 20–50 Ω ⁻¹ cm ⁻¹ ）和Mn ₃ Ge。尽管 Mn _2.4 Ga 的三角形自旋结构显示出每个公式单元 ≈0.05 µ _B 的弱净磁矩，但它保证了戈薇平面中的非零贝里曲率。此外，反常霍尔电导率随着小磁场的旋转而表现出符号反转，这可以归因于自旋三角形结构的场控手性。该理论计算进一步表明，Mn _2.4 Ga 中的大 AHE 源于与靠近 Weyl 点的费米能级调整相关的贝里曲率的显着增强。这些特性，加上使用适度的外部磁场操纵力矩方向的能力，使得 Mn _2.4 Ga 对于未来的反铁磁自旋电子学来说非常令人兴奋。

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Large Anomalous Hall Effect at Room Temperature in a Fermi-Level-Tuned Kagome Antiferromagnet

The recent discoveries of surprisingly large anomalous Hall effect (AHE) in antiferromagnets have attracted much attention due to their promising use in spintronics devices. However, such AHE-hosting antiferromagnetic materials are rare in nature. Herein, it is demonstrated that Mn_2.4Ga, a Fermi-level-tuned kagome antiferromagnet, has a large anomalous Hall conductivity of ≈150 Ω⁻¹ cm⁻¹ at room temperature that surpasses the usual high values (i.e., 20–50 Ω⁻¹ cm⁻¹) observed so far in two outstanding kagome antiferromagnets, Mn₃Sn and Mn₃Ge. Although the triangular spin structure of Mn_2.4Ga shows a weak net magnetic moment of ≈0.05 µ_B per formula unit, it guarantees a nonzero Berry curvature in the kagome plane. Moreover, the anomalous Hall conductivity exhibits a sign reversal with the rotation of a small magnetic field that can be ascribed to the field-controlled chirality of the spin triangular structure. This theoretical calculations further suggest that the large AHE in Mn_2.4Ga originates from a significantly enhanced Berry curvature associated with the tuning of the Fermi level close to the Weyl points. These properties, together with the ability to manipulate moment orientations using a moderate external magnetic field, make Mn_2.4Ga extremely exciting for future antiferromagnetic spintronics.

更新日期：2024-02-27

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