Catalogue of phonon modes in several cuprate high-temperature superconductors from density functional theory

Abstract

Cuprates are promising candidates for study in developing higher temperature superconductors. A thorough understanding of a material's phonon modes enables further investigation of its emergent properties, however, no complete reference of the phonon modes exists. Here, using density functional theory, we evaluate the phonon frequencies and atomic displacements for ${\text{La}}_2{\text{CuO}}_4$, ${\text{Bi}}_2{\text{Sr}}_2{\text{CuO}}_6$, and ${\text{Bi}}_2{\text{Sr}}_2{\text{CaCu}}_2{\text{O}}_8$ in their tetragonal structures. The phonon modes for all materials agree with those expected from space group symmetry and display instabilities corresponding to known low-temperature structural phase transitions.

22 pages, 10 figures