We reinvestigate the pressure dependence of the crystal structure and antiferromagnetic phase transition in ${\mathrm{MnTe}}_2$ using the rigorous and reliable tool of high-pressure neutron powder diffraction. First-principles density functional theory calculations are carried out in order to gain microscopic insight. The measured Néel temperature of ${\mathrm{MnTe}}_2$ is found to show unusually large pressure dependence of $12\text{K}{\text{GPa}}^{-1}$. This gives rise to a large violation of Bloch's rule given by $\mathrm{<ruby><rb>\alpha </rb><rt>あるふぁ</rt></ruby>}=\frac{dlog{T}_N}{dlogV}=-\frac{10}{3}\approx -3.3$, to an $\mathrm{<ruby><rb>\alpha </rb><rt>あるふぁ</rt></ruby>}$ value of $-6.0\pm 0.1$ for ${\mathrm{MnTe}}_2$. The ab initio calculation of the electronic structure and the magnetic exchange interactions in ${\mathrm{MnTe}}_2$ for the measured crystal structures at different pressures indicates the pressure dependence of the Neél temperature $\mathrm{<ruby><rb>\alpha </rb><rt>あるふぁ</rt></ruby>}$ is $-5.61$, in close agreement with experimental findings. The microscopic origin of this behavior turns out to be dictated by the distance dependence of the cation-anion hopping interaction strength.

• Received 23 October 2014
• Revised 25 February 2015

DOI:https://doi.org/10.1103/PhysRevB.91.104412