ELECTRONIC STRUCTURE AND RELATED PROPERTIES OF RARE EARTH TRANSITION METAL BOROCARBIDES -LDA BANDSTRUCTURE ANALYSIS

摘要

As an overview, we demonstrate that bandstructure calculations using the local density approximation are an appropriate tool to get detailed insight into the electronic structure and properties derived from of rare earth transition metal borocarbides. Structural parameters for ScNi_2B_2C derived from total energy calculation allow to discriminate conflicting experimental structural reports. A strong coupling of the charge degrees of freedom to the Raman active A_(1_g) boron-phonon is shown for YPd_2B_2C. The calculated Fermi surfaces show large anisotropies and extended nesting regions for various superconducting compounds, whereas for the non-superconducting LaNi_2B_2C no nesting was found. The influence of disorder on the electronic structure is investigated using the coherent potential approximation.