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Based on ab initio electronic structure calculations of chalcopyrite CuAl1-xSnxS2 (CASS) and Cu1-xVCuxAlS2 (CVAS) by the Korringa-Kohn-Rostoker coherent-potential-approximation (KKR-CPA) method within the self-interaction-corrected local density approximation (SIC-LDA), we design a new class of n-type CASS and p-type CVAS transparent conducting sulfides with a negative activation energy (NAE) for application in high-efficiency photovoltaic solar cells (PVSCs). The Sn impurity in the CASS forms the hyper-deep bonding state (HDBS) below the valence band, and the localized Fano-antiresonance anti-bonding donor state with NAE is pushed up into the conduction band. The Cu vacancy (VCu) in the CVAS forms non-bonding S dangling bonds in the mid-valence band and acts as an acceptor with NAE. [ABSTRACT FROM AUTHOR]

Based upon ab initio electronic structure calculations by the Korringa–Kohn–Rostoker coherent potential approximation and Monte Carlo simulation of the two-dimensional spinodal nano-decomposition, we simulate the formation of a self-organized quasi-one-dimensional nano-structure (Konbu-Phase) under a layer-by-layer crystal growth condition of Cu–Ni alloy. We propose a new mechanism of the giant Peltier coefficient dramatically enhanced by the one-dimensional singular density of states in the Konbu-Phase in addition to the conventional Peltier cooling and the spin-entropy expansion cooling. [ABSTRACT FROM AUTHOR]

Based on the first-principles calculations within the self-interaction-corrected local density approximation, we propose a materials design for high efficiency photovoltaic solar cells. By using the Korringa–Kohn–Rostoker coherent potential approximation method, the electronic structure and mixing energy of CuIn1-xGaxSe2 (CIGS) are calculated. It is found that (1) CIGS has positive and convex mixing energy; thus, it has a tendency towards spinodal nano-decomposition, and (2) the band alignment between CuInSe2 and CuGaSe2 is type II. Based on these findings, it is pointed out that efficient electron–hole separation and multiexciton effect upon photoexcitation can be expected in the spinodal decomposed CIGS for realizing high-efficiency energy conversion. [ABSTRACT FROM AUTHOR]

Electronic structure of rutile-TiO2 based dilute magnetic semiconductors (DMS) are investigated within self-interaction-corrected local density approximation (SIC-LDA). These results are compared with those calculated within standard LDA. We employ the Korringa–Kohn–Rostoker method combined with coherent potential approximation. It is found that high-spin state in (Ti,Co)O2 with O vacancy is predicted in the SIC-LDA. This result is in good agreement with the experimental results. As a result, we find that O vacancy in (Ti,Co)O2 is the origin of Co2+ high-spin state and SIC-LDA is indispensable to describe the correct electronic structure and spin state of TiO2-based DMS. [ABSTRACT FROM AUTHOR]