Dulal Rajendra P, Dahal Bishnu R, Forbes Andrew, Bhattarai Niraj, Pegg Ian L, Philip John
Department of Physics, The Catholic University of America, Washington, DC, 20064, USA.
The Vitreous State Laboratory, The Catholic University of America, Washington, DC, 20064, USA.
Sci Rep. 2019 Mar 4;9(1):3342. doi: 10.1038/s41598-019-39037-0.
Several cobalt-based Heusler alloys have been predicted to exhibit Weyl Semimetal behavior due to time reversal symmetry breaking. CoTiGe is one of the predicted ferromagnetic Weyl semimetals. In this work, we report weak localization and small anomalous Hall conductivity in half-metallic CoTiGe thin films grown by molecular beam epitaxy. The longitudinal resistivity shows semimetallic behavior. Elaborate analysis of longitudinal magnetoconductance shows the presence of a weak localization quantum correction present even up to room temperature and reduction in dephasing length at lower temperature. Negative longitudinal magnetoresistance is observed from 5 to 300 K, but at 300 K magnetoresistance becomes positive above 0.5 T magnetic field. The anomalous Hall effect has been investigated in these thin films. The measured anomalous Hall conductivity decreases with increasing temperature, and a small anomalous Hall conductivity has been measured at various temperatures which may be arising due to both intrinsic and extrinsic mechanisms.
由于时间反演对称性破缺，几种钴基赫斯勒合金被预测会表现出外尔半金属行为。CoTiGe是预测的铁磁外尔半金属之一。在这项工作中，我们报道了通过分子束外延生长的半金属CoTiGe薄膜中的弱局域化和小反常霍尔电导率。纵向电阻率表现出半金属行为。对纵向磁导率的详细分析表明，即使在室温下也存在弱局域化量子修正，并且在较低温度下退相干长度减小。在5到300 K范围内观察到负纵向磁电阻，但在300 K时，在磁场高于0.5 T时磁电阻变为正。已经对这些薄膜中的反常霍尔效应进行了研究。测量的反常霍尔电导率随温度升高而降低，并且在不同温度下测量到了小的反常霍尔电导率，这可能是由本征和非本征机制共同引起的。
