The electronic structure of PrT2B2C (T=Co,Ni and Pt) : A Tight Binding - Extended Huckel

The calculations reported in this work were carried out by means of the tight-binding method within the Extended Huckel framework using {\sc YAeHMOP} computer package with f-orbitals. The calculated energy bands indicate that the three compounds under investigation show metallic behavior mainly caused by the d-states of the $\rm \bf {T}$-atoms. For $\rm \bf {PrNi_2B_2C}$ and $\rm \bf {PrCo_2B_2C}$ compounds the Fermi level ($\rm \bf {E_F}$) is located in a valley in the total density of states ($\rm \bf {DOS}$), while for $\rm \bf {PrPt_3B_2C}$ the $\rm \bf {E_F}$ is located in a crest. Our results predict the absence of superconductivity in $\rm \bf {PrNi_2B_2C}$ and $\rm \bf {PrCo_2B_2C}$ compounds, while the enhancement of $\rm \bf {DOS}$ at the $\rm \bf {E_F}$ in $\rm \bf {PrPt_2B_2C}$ compound indicates the possibility of superconductivity. Moreover, the $\rm \bf {PrNi_2B_2C}$ and $\rm \bf {PrCo_2B_2C}$ compounds indicate strong and similar type of hybridization while different and reduced hybridization in $\rm \bf {PrPt_2B_2C}$ compound is observed. Transport properties performed by our group confirms the existence of superconductivity in $\rm \bf {PrPt_2B_2C}$ while the high value of Sommerfeld constant ($\gamma$ $\approx$ 200-300 $\rm mJ/mol-K^2$) in $\rm \bf {PrNi_2B_2C}$ and $\rm \bf {PrCo_2B_2C}$ compounds might be connected by an enhancement of the hybridization observed here.