Waterfall (IMAGE) DOE/Oak Ridge National Laboratory Caption Neutron scattering experiments performed at ORNL show that lead telluride exhibits a strong anharmonic coupling between its optical and acoustic lattice vibrations, with a drop in thermal conductivity resembling a waterfall in this data image. This newly discovered coupling helps explain the low thermal conductivity that makes lead telluride a promising material for thermoelectric devices. Credit ORNL Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.