Entropy-Driven Clustering in Tetrahedrally Bonded Multinary Materials

Clustering of certain structural motifs leads to fluctuations of the electrostatic potential in an entire class of materials that are of interest as solar absorbers, and controlling such fluctuations is important for photovoltaic applications. The authors show that this clustering is driven by entropy and leads to narrowing of the band gap, and may occur even under low-temperature growth conditions. They also note that this cluster formation could actually be advantageous for thermoelectric applications.