Thermal Transports Of One-dimensional Carbon Nanostructures

Low-dimensional materials,especially one-dimensional materials,have been widely concerned due to their excellent physical properties.In recent years,a variety of one-dimensional carbon nanomaterials have been synthesized with the development and progress of the nanotechnology,such as nanothreads and nanobuds.There are a number of studies on nanowires which have a certain diameter and size in the past decades.However,there are only a few studies of atomic and molecular chains for nanothreads up to now.Therefore,it is quite meaningful and necessary to study the thermal transport of these materials,so as to provide a theoretical basis for the application of these new one-dimensional carbon nanomaterials in our life.The paper is divided into the following five chapters:The first chapter introduces the research background and thermal transport of one-dimensional carbon nanomaterials and nanowires.The second chapter introduces the molecular dynamics and green's function method.In the third chapter,thermal transports of several nanothreads are studied with green's function method.We found that thermal conductance of these nanothreads varies greatly due to the different connectivity styles.Then,we proposed a simplified model is to simplify and study these nanothreads.The results show that the degree of saturation and the number of phonon transport channel play an important role in nanothreads'thermal transport,and different components coupling of force constant also change the thermal transport of nanothreads great.In the fourth chapter,we studied thermal transport of nanobuds with green's function and molecular dynamics method,and different factors which influence thermal transport are studied with simplified models.The results of molecular dynamics method show that thermal conductance of nanobuds decrease with the increase of C₆₀'s number till a convergent value.Results from simplified model show the same trend of variation,which prove the rationality of the simplified model.Then,which influence thermal transport of nanobuds are studied with the simplified model.The results show that interactions between C₆₀ and carbon nanotube contribute more to thermal transport than that between C₆₀s,which will provide some reference for the application of nanobuds in thermal materials and thermal devices.In the fifth chapter,we summary the result of our study and describe the future of study.