 This paper analyzes the impact of reducing lattice thermal conductivity, CAPA-L, on Z-T improvements, using electrical conductivity, sigma, total thermal conductivity, total, and Lorenz number, Vell. The Weidman-Franz law is used to estimate electronic component of thermal conductivity, CAPA-E, from sigma measurements. However, significant deviations from the degenerate limit occur for non-degenerate semiconductors, where L converges to 1.5 times 10 minus 8 W omega k minus 2 for acoustic phonon scattering. The decrease in L is correlated with an increase in thermal power, absolute value of C-beck coefficient S. A first-order correction to the degenerate limit of L can be based on measured thermal power, independent of temperature or doping. The equation proposed is L equals 1.5 plus exp, dash 0.7 S, and is accurate within 5 percent for single parabolic band slash acoustic phonon scattering assumption and within 20 percent for PbC, PbS, PbT, C0.8 go 0.2. Using this equation for L instead of a constant value will significantly improve the estimation of lattice thermal conductivity when detailed band structure and scattering mechanism is not known. This article was authored by Hyunsik Kim, Zachary M. Gibbs, Inglutang, and others. We are article.tv, links in the description below.