Adjusting the thermal conductivity of materials is a key focus in nanoscience. And it is becoming increasingly more important now that components in the electronics and computer industry are becoming ever smaller and more powerful, according to a press release from the University of Basel.
Researchers from the University of Basel have now teamed up with colleagues from the Netherlands (Eindhoven University of Technology) and Spain (Universitat Autònoma de Barcelona and Institut de Ciència de Materials de Barcelona) to make an important discovery in this field. They focused on mechanical waves, known as phonons, which are responsible for heat generation.
Phonons are extremely important in nanoscience, and materials are now being designed that can be used to control the propagation of phonons. According to the press release, one aim is to produce materials that can release heat very quickly, and, as a result, heat up as little as possible. Another aim is to maintain temperature differences for as long as possible in order to use them for power generation.
The Basel researchers have now demonstrated that the thermal conductivity in nanowires can be controlled through the arrangement of atoms alone. Headed by Professor Ilaria Zardo, the group from the University of Basel’s Department of Physics and Swiss Nanoscience Instituteproduced “gallium phosphide nanowries in which successive crystal layers are periodically rotated against each other by 60 degrees”. In previous experiments, different materials were used for the crystal layers, which resulted in interference effects.
The Basel researchers have now proved that such interference effects “do not occur if the material of the layers is identical but the arrangement of the atoms differs”. This shows for the first time that “the arrangement of the atoms alone influences the phonons and thus the thermal conductivity”.