Quantum Transport Properties Of Gate-tunable Endohedral Boron Fullerene

Recently,boron fullerenes with stable structure have attracted intensive research interest.Formed by enclosing metal atoms in the fullerene cage,endohedral boron fullerenes are more stable and exhibit extraordinary physical and chemical properties,which make endohedral boron fullerenes potential candidates in nanoelectronics and related areas.In this thesis,by combining the nonequilibrium Green's function formalism,density functional theory,and scatting matrix method,the quantum transport properties of systems that consist of metallic aluminum leads and Sc₃N@B₈₀0 molecule are studied in detail.Two geometric configurations with the Sc₃N plane vertical or parallel relative to the transport direction are considered,and the effect of gate voltage is discussed.Research works in the thesis are mainly:?1?In conducting regime,two geometric configurations have the same static property.In conducting regime,transport properties of the two geometric configurations show similar behaviors,and can be effectively tuned by the gate voltage.The charge relaxation and charge distribution resistances,which label the charge fluctuations in the system,are very small in this regime.The effective resistances at the Fermi level exhibit negative differential resistance with respect to positive gate voltage.?2?In tunneling regime,two configurations have distinct resonant peaks in transmission and density of states curves,which shows that the micro structure of Sc₃N has a large impact on the transport properties of tunneling systems.The effective resistances are greatly enhanced at the resonant energy levels.The system with vertical configuration can be effectively tuned by the gate voltage,and shows on-off,negative differential resistance phenomena with respect to gate voltage.In contrast,the system with parallel configuration has little response to gate voltage.