LINEAR SCALING METHOD FOR PHONON CALCULATIONS FROM ELECTRONIC-STRUCTURE

We present a method for phonon spectrum calculations from electronic s tructure calculations that scales linearly with system size. It allows computation of the dynamical matrix and phonon structure of systems o f unprecedented size. The method is based on (i) use of localized wave functions to describe the electronic states, (ii) truncation of the d ynamical matrix beyond a cutoff, and (iii) reconstruction of the spect rum of the sparse dynamical matrix by the maximum entropy approach of Drabold and Sankey. We test the method with a tight-binding Hamiltonia n for carbon, on a 216 atom supercell in the diamond structure, and in fullerene balls of up to 3840 atoms.