法伟
南京大学物理学院
报告时间：6月9日 中午12：15
报告地点：唐楼 B501
Abstract: Motivated by the recent successful synthesis and observation of a new warped, double-concave graphene "Pringle" (Nat. Chem., 2013, 5, 739) and an all-boron fullerene (Nat. Chem. 2014, 6, 727), we investigate structural and electronic properties of warped boron-nitride (BN) analogue and metal-encapsulating boron fullerene MB40 (M = Li, Na, K, Ba, Nd, and Tl) using density-functional theory calculations. It is found that the Na, Nd, and Ba atoms can be stably encapsulated inside the B40 cage, while the Li, K, and Tl dopants favor the hepta-hapto exohedral configuration. Besides the atomic size matching, another key factor that affects preference of endohedral versus exohedral configuration of metalloborospherenes is the interaction between the dopant and B atoms. A potential energy scan of the metal dopant moving from the cage center through a heptagon ring of B40 can be a cost-effective computational indicator to examine likelihood of forming endohedral complexes.
It is also found that the warped BN nanoplate with one pentagon and five heptagons are stable without imaginary frequencies. The warped B40N40H30 is expected to be flexible in solution as it can periodically change their shape in a dynamic "flapping" fashion due to their much lower activation barrier of racemization compared to that of the C80H30 counterpart. Since the warped B40N40H30 possesses a smaller HOMO–LUMO gap than the planar B39N39H30, it is expected that incorporating non-hexagonal ring defects by design can be an effective way to modify electronic properties of BN-based nanoplates.