First-principal investigations of the electronic, magnetic, and thermoelectric properties of CrTiRhAl quaternary Heusler alloy

Density functional theory (DFT) calculations were performed to investigate the electronic, magnetic, and thermoelectric properties of CrTiRhAl quaternary Heusler alloy (QHA). The type-I atomic configuration was found to be the most stable structure of this alloy. The CrTiRhAl QHA was also found to exhibit a semiconducting behavior with an indirect narrow gap of 0.129 eV at the majority spin channel. On the other hand, the minority spin channel exhibits a metallic behavior. The QHA has a total magnetic moment of 2 mu B and 100 % spin-polarization that making it ideal for potential spintronic applications. The Seebeck coefficient, electrical conductivity, and electronic thermal conductivity of CrTiRhAl alloy were calculated using the semi-classical Boltzmann theory. Additionally, the lattice thermal conductivity was predicted using Slack's equation. The calculations predicted a low figure of merit (ZT) below the Curie temperature, namely 0.4 at 300 K, which can be enhanced by lowering the structural dimensionality or doping for possible thermoelectric applications. However, the ZT value dropped drastically beyond Curie temperature (0.02 at 800 K).