Uncovering the behavior of Hf2Te2P and the candidate Dirac metal Zr2Te2P

TL;DR

This study investigates the electronic properties of Hf2Te2P and Zr2Te2P, revealing their Fermi liquid behavior, quasi-two-dimensional Fermi surfaces, and potential for hosting Dirac physics, supported by experimental and theoretical analyses.

Contribution

It provides detailed experimental and theoretical characterization of Hf2Te2P and Zr2Te2P, highlighting their potential as Dirac materials and the influence of spin-orbit coupling.

Findings

Both materials exhibit Fermi liquid behavior at low temperatures.

Quantum oscillations indicate quasi-two-dimensional Fermi surfaces.

Zr2Te2P has a very small effective mass of 0.046m0.

Abstract

Results are reported for single crystal specimens of Hf$_2$Te$_2$P and compared to its structural analogue Zr$_2$Te$_2$P, which was recently proposed to be a potential reservoir for Dirac physics.[1] Both materials are produced using the iodine vapor transport method and the resulting crystals are exfoliable. The bulk electrical transport and thermodynamic properties indicate Fermi liquid behavior at low temperature for both compounds. Quantum oscillations are observed in magnetization measurements for fields applied parallel but not perpendicular to the $c$-axis, suggesting that the Fermi surfaces are quasi-two dimensional. Frequencies are determined from quantum oscillations for several parts of the Fermi surfaces. Lifshitz-Kosevich fits to the temperature dependent amplitudes of the oscillations reveal small effective masses, with a particularly small value $m^*$ $=$ 0.046$m_0$ for the {\alpha} branch of Zr$_2$Te$_2$P. Electronic structure calculations are in good agreement with quantum oscillation results and illustrate the effect of a stronger spin-orbit interaction going from Zr to Hf. These results suggest that by using appropriate tuning parameters this class of materials may deepen the pool of novel Dirac phenomena.