We report on the single crystal growth and transport properties of a topological semimetal CaAgBi which crystallises in the hexagonal ABC−type structure with the non-centrosymmetric space group P63mc (No. 186). The transverse magnetoresistance measurements with current in the basal plane of the hexagonal crystal structure reveal a value of about 30 % for I // [10-10] direction and about 50 % for I // [1-210] direction at 10 K in an applied magnetic field of 14 T. The magnetoresistance shows a cusp-like behavior in the low magnetic-field region, suggesting the presence of weak antilocalization effect for temperatures less than 100 K. The Hall measurements reveal that predominant charge carriers are p type exhibiting a linear behavior for fields up to 14 T and can be explained based on the single band model. The magnetoconductance of CaAgBi is analysed based on the modified Hikami-Larkin-Nagaoka (HLN) model. Our first-principles calculations within a density-functional theory framework reveal that CaAgBi supports a topological Dirac semimetal state with Dirac points located on the rotational axis slightly above the Fermi level and are protected by C6v point-group symmetry. The Fermi surface consists of both the electron and hole pockets. However, the size of hole pockets is much larger than electron pockets suggesting the dominant p type carriers in accord with our experimental results.
@article{arxiv.1910.00545,
title = {Weak antilocalization in a noncentrosymmetric CaAgBi single crystal},
author = {Souvik Sasmal and Rajib Mondal and Ruta Kulkarni and Bahadur Singh and A. Thamizhavel},
journal= {arXiv preprint arXiv:1910.00545},
year = {2020}
}