Putative hybridization gap in CaMn$_{2}$Bi$_{2}$ under applied pressure

M. M. Piva; S. M. Thomas; Z. Fisk; J. -X. Zhu; J. D. Thompson; P. G. Pagliuso; P. F. S. Rosa

doi:10.1103/PhysRevB.100.045108

paper

Putative hybridization gap in CaMn $_{2}$ Bi $_{2}$ under applied pressure

arXiv:1907.09984 · doi:10.1103/PhysRevB.100.045108

Abstract

We report electrical transport measurements on CaMn $_{2}$ Bi $_{2}$ single crystals under applied pressure. At ambient pressure and high temperatures, CaMn $_{2}$ Bi $_{2}$ behaves as a single-band semimetal hosting Néel order at $T_{N} = 150$ ~K. At low temperatures, multi-band behavior emerges along with an activated behavior typical of degenerate semiconductors. The activation gap is estimated to be $Δ \sim 20$ ~K. Applied pressure not only favors the antiferromagnetic order at a rate of 0.40(2)~K/kbar, but also enhances the activation gap at $20$ ~kbar by about $70$ ~\%. This gap enhancement is typical of correlated narrow-gap semiconductors such as FeSi and Ce $_{3}$ Bi $_{4}$ Pt $_{3}$ , and places CaMn $_{2}$ Bi $_{2}$ as a Mn-based hybridization-gap semiconductor candidate. \textit{Ab initio} calculations based on the density functional theory are shown to be insufficient to describe the ground state of CaMn $_{2}$ Bi $_{2}$ .

7 pages, 5 figures

Putative hybridization gap in CaMn2​Bi2​ under applied pressure

Abstract

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Putative hybridization gap in CaMn $_{2}$ Bi $_{2}$ under applied pressure