Magnetic mixed valent semimetal EuZnSb_{2} with Dirac states in the band structure

Abstract

We report discovery of antiferromagnetic semimetal EuZnSb_{2}, obtained and studied in the form of single crystals. Electric resistivity, magnetic susceptibility, and heat capacity indicate antiferromagnetic order of Eu with T_{N} = 20 K. The effective moment of Eu^{2+} inferred from the magnetization and specific heat measurement is 3.5 μ_{B}, smaller than the theoretical value of Eu^{2+} due to presence of both Eu^{3+} and Eu^{2+}. Magnetic-field-dependent resistivity measurements suggest dominant quasi-two-dimensional Fermi surfaces whereas the first-principle calculations point to the presence of Dirac fermions. Therefore, EuZnSb_{2} could represent the first platform to study the interplay of dynamical charge fluctuations, localized magnetic 4f moments, and Dirac states with Sb orbital character.