Calculation of electronic properties of SrSi2 within the framework of a band theory

Results of the electronic property calculations of SrSi2 using the density-functional theory and the local density approximation with the generalized gradient correction are presented. The calculated structural parameters are in good agreement with the experimental values. The nearest Si–Si bond has a covalent nature. The electron density distribution belonging to the highest valence band (HVB) along this bond has a minimum in the center of this bond while that belonging to the lowest conduction band (LCB) has a maximum in the center of this bond. The calculated energy difference between the bottom of the LCB and the top of the HVB becomes smaller and changes to negative values by decreasing the cell volume. This agrees with the observed gap shrinkage by compression, though the observe gap between the HVB and LCV at ambient pressure could not be reproduced by the present band calculation as in the cases of other polar semiconductors.