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arXiv · 1604.03931

Quasi-two-dimensional Dirac fermions and quantum magnetoresistance in LaAgBi$_2$

Kefeng Wang·D. Graf·C. Petrovic
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Abstract

We report quasi-two-dimensional Dirac fermions and quantum magnetoresistance in LaAgBi$_2$. The band structure shows several narrow bands with nearly linear energy dispersion and Dirac-cone-like points at the Fermi level. The quantum oscillation experiments revealed one quasi-two-dimensional Fermi pocket and another complex pocket with small cyclotron resonant mass. The in-plane transverse magnetoresistance exhibits a crossover at a critical field $B^*$ from semiclassical weak-field $B^2$ dependence to the high-field unsaturated linear magnetoresistance which is attributed to the quantum limit of the Dirac fermions. Our results suggest the existence of quasi 2D Dirac fermions in rare-earth based layered compounds with two-dimensional double-sized Bi square nets, similar to (Ca,Sr)MnBi$_{2}$, irrespective of magnetic order.

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Kefeng Wang, D. Graf, C. Petrovic. 2016-04-13. Quasi-two-dimensional Dirac fermions and quantum magnetoresistance in LaAgBi$_2$. https://doi.org/10.1103/physrevb.87.235101

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