凝聚态物理
磁电阻
物理
弱局部化
电阻率和电导率
半经典物理学
简并能级
电子能带结构
半金属
兴奋剂
量子
磁场
量子力学
带隙
作者
Sudip Malick,A. Ghosh,Chanchal K. Barman,Aftab Alam,Zakir Hossain,P. Mandal,J. Nayak
出处
期刊:Physical review
日期:2022-04-05
卷期号:105 (16)
被引量:4
标识
DOI:10.1103/physrevb.105.165105
摘要
The effect of 50% Cu doping at the Au site in the topological Dirac semimetal CaAuAs is investigated through electronic band structure calculations, electrical resistivity, and magnetotransport measurements. Electronic structure calculations suggest a broken-symmetry-driven topological phase transition from the Dirac to triple-point state in CaAuAs via alloy engineering. The electrical resistivity of both the CaAuAs and ${\mathrm{CaAu}}_{0.5}{\mathrm{Cu}}_{0.5}\mathrm{As}$ compounds shows metallic behavior. Nonsaturating quasilinear magnetoresistance (MR) behavior is observed in CaAuAs. On the other hand, MR of the doped compound shows a pronounced cusplike feature in the low-field regime. Such behavior of MR in ${\mathrm{CaAu}}_{0.5}{\mathrm{Cu}}_{0.5}\mathrm{As}$ is attributed to the weak antilocalization (WAL) effect. The WAL effect is analyzed using different theoretical models, including the semiclassical $\ensuremath{\sim}\sqrt{B}$ one which accounts for the three-dimensional WAL and the modified Hikami-Larkin-Nagaoka model. A strong WAL effect is also observed in the longitudinal MR, which is well described by the generalized Altshuler-Aronov model. Our study suggests that the WAL effect originates from weak disorder and the spin-orbit coupled bulk state. Interestingly, we have also observed the signature of chiral anomaly in longitudinal MR when both the current and field are applied along the $c$ axis. The Hall resistivity measurements indicate that the charge conduction mechanism in these compounds is dominated by the holes with a concentration $\ensuremath{\sim}{10}^{20}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$ and mobility $\ensuremath{\sim}{10}^{2}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{2}\phantom{\rule{4pt}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{4pt}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$.
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