SILICON VACANCY - POSSIBLE ANDERSON NEGATIVE-U SYSTEM

This Letter analyzes the electron states associated with the silicon vacancy and proposes a distortion model for the surrounding atoms that is derived from self-consistent calculations for single-particle states and from model calculations of elastic restoring forces. The predicted level structure is such that V+ is, contrary to currently accepted ideas, a metastable state which decays either to V0 or to V++, depending on the Fermi energy. © 1979 The American Physical Society.