Progress towards understanding ultranonlocality through the wave-vector and frequency dependence of approximate exchange-correlation kernels

Article

关键词: DENSITY-FUNCTIONAL THEORY;    TOTAL-ENERGY CALCULATIONS;    EXCITATIONS;   

DOI  :  10.1103/PhysRevB.104.125112

来源: SCIE

【 摘 要 】

In the framework of time-dependent density functional theory (TDDFT), the exact exchange-correlation (xc) kernel f(xc)(n, q, omega) determines the ground-state energy, excited-state energies, lifetimes, and the time-dependent linear density response of any many-electron system. The recently developed MCP07 xc kernel f(xc)(n, q, omega) of Ruzsinszky et al. [Phys. Rev B 101, 245135 (2020)] yields excellent uniform electron gas (UEG) ground-state energies and plausible plasmon lifetimes. As MCP07 is constructed to describe f(xc) of the UEG, it cannot capture optical properties of real materials. To verify this claim, we follow Nazarov et al. [Phys. Rev. Lett. 102, 113001 (2009)] to construct the long-range, dynamic xc kernel, lim(q -> 0) f(xc)(n, q, omega) = -alpha(omega)e(2)/q(2), of a weakly inhomogeneous electron gas, using MCP07 and other common xc kernels. The strong wave-vector and frequency dependence of the ultranonlocality coefficient alpha(omega) is demonstrated for a variety of simple metals and semiconductors. We examine how imposing exact constraints on an approximate kernel shapes alpha(omega). Comparisons to kernels derived from correlated-wave-function calculations are drawn.

【 授权许可】

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