An analytic method for calculating stress induced changes in Fermi surfaces

Abstract

A method is described which drives analytic expressions for stress induced changes in Fermi surfaces. The authors differentiate a small folded down secular equation in a region of k space close to the symmetry point k₀. The fractional change in cross sectional area for the K point in the hcp Brillouin zone is found to be delta lnA/ delta sigma =B delta (E_F-E_k)/ delta sigma -C delta V/ delta lnq, where B and C are coefficients whose values depend on the parameters E_F, E_K, V and S-V and S being pseudopotential and spin-orbit coupling matrices, respectively. These parameters may be extracted from any well fitted band structure calculation, and together with the elastic constants may be used to evaluate delta lnA/ delta sigma . Comparison of theory with experiment is made for the zinc third band electron needles, and for the cigars in beryllium and magnesium. The agreement is in general satisfactory and, more importantly, leads to an understanding of the results.