A new practical scheme for the optimized effective potential method

Although the optimized effective potential (OEP) method is a powerful method for going beyond the local density approximation of the density functional theory, it has not been widely used for extended systems. One of the reasons for this is that the OEP schemes used thus far contain an indefinite constant for extended systems that has to be determined in an ad hoc manner. In this paper, we propose a new practical scheme which enables us to determine the OEP without any such ambiguity. The principle is to determine the indefinite constant by imposing the requirement that the total energy be minimized. We apply the present scheme, in an exchange-only version, to crystalline alkali metals (Li, Na, and K), ferromagnetic Fe, and antiferromagnetic MnO.