Abstract:
The Tantalum-Rhodium-Boride (TaRh2B2) and Niobium-Rhodium-Boride(NbRh2B2) compounds exhibit noncentrosymmetric superconductivity with a chiral structure. To explore their fascinating physics and physical properties; an ab-initio density functional theory approach is used. The structural properties, mechanical stability, ductility, Debye temperature, melting temperature, Tm, electronic characteristics, optical response to incident photon energy, and superconducting transition temperature, Tc, of chiral TaRh2B2 and NbRh2B2 compounds are investigated and thoroughly discussed in this study. Both the chiral compounds are mechanically stable and exhibit a ductile nature with and without pressure. The maximum value of the Pugh ratio (an indicator of ductile/brittle behaviors) is observed to be 2.55 (for NbRh2B2) and 2.52 (for TaRh2B2) at 16 GPa. The lowest value of the Pugh ratio (2.16 for TaRh2B2 and 2.32 for NbRh2B2) is noticed at zero pressure for both compounds. The TaRh2B2 exhibits a higher Tm compared to that of the NbRh2B2 under the studied pressure. The electronic structure calculation indicates both compounds are metallic in nature, and the saddle points are close to fermi level in the electronic band diagram, which also indicates the superconducting behavior of these compounds with and without pressure.At zero pressure, the calculated densities of states (DOSs) at the Fermi level are found to be 1.60 and 2.06 states eV-1 per formula unit for TaRh2B2 and NbRh2B2 compounds, respectively. The DOS values of both chiral compounds do not alter significantly with applied pressure. The analysis of reflectivity spectra suggests that both chiral compounds can be used as efficient reflecting materials in the visible energy region. The pressure-induced variation of Debye temperatures of both compounds is observed, which may cause the alternation of the Tc with applied pressure.
