Charge density wave formation in nanocrystals

This chapter discusses charge density wave formation in nanocrystals. Physics in nanometer scale structures has attracted much interest during the last few decades because of enhanced quantum effects in these small systems. The study of nanostructures is, in part, motivated by the trend toward smaller devices in the semiconductor industry. As the elements in devices achieve nanometer dimensions, it is necessary to investigate the role of quantum confinement of electrons to understand new phenomena that manifest themselves in these nanoscale structures. The artificial nanometer structures used in this study range from semiconductor or metallic nanostructures fabricated by modern lithographic technologies to chemically synthesized nanocrystals. Various mesoscopic phenomena such as single electron tunneling, energy level quantization, phase coherence, and quantum transport have been intensively studied in these confined nanostructures. In addition to the investigation of enhanced quantum effects in confined structures, these systems enable one to understand the change of physical properties evolved from isolated atoms or small molecules to an infinite bulk phase. For example, well-defined discrete quantum levels of an atom/molecule are related to the electronic band structure of the bulk.