Effect of structure on the electronic density of states of doped lanthanum cuprate.

We present a series of detailed band calculations on the various structural phases of doped lanthanum cuprate: HTT, LTO, and LTT. The LTO distortion is shown to have little effect on the electronic density of states (DOS). A fit to the pressure dependence of the superconducting transition temperature indicates that only 2.5% of the DOS is affected by the HTT→ LTO transition. The LTT distortion also has little effect on the DOS for the experimental value of the octahedral tilt angle. Larger tilt angles, though, lead to a dramatic change in the DOS.