In this paper, we discuss the positive definite problem of a binary quartic form and obtain a necessary and sufficient condition. In addition we give two examples to show that there are some errors in the paper [1].
We investigate the inter-well coupling of multiple graphene quantum well structures consisting of graphenesuperlattices with different periodic potentials.The general form of the eigenlevel equation for the bound stat...We investigate the inter-well coupling of multiple graphene quantum well structures consisting of graphenesuperlattices with different periodic potentials.The general form of the eigenlevel equation for the bound states of thequantum well is expressed in terms of the transfer matrix elements.It is found that the electronic transmission exhibitsresonant tunneling peaks at the eigenlevels of the bound states and shifts to the higher energy with increasing the incidentangle.If there are N coupled quantum wells,the resonant modes have N-fold splitting.The peaks of resonant tunnelingcan be controlled by modulating the graphene barriers.展开更多
文摘In this paper, we discuss the positive definite problem of a binary quartic form and obtain a necessary and sufficient condition. In addition we give two examples to show that there are some errors in the paper [1].
基金Supported by the National Natural Science Foundation of China under Grant No. 10832005the Program for Changjiang Scholars and Innovative Research Team in University under Grant No. IRT0730+1 种基金Program for International S & T Cooperation Program of China under Grant No. 2009DFA02320Doctoral Research Foundation of Nanchang University under Grant No. 300715
文摘We investigate the inter-well coupling of multiple graphene quantum well structures consisting of graphenesuperlattices with different periodic potentials.The general form of the eigenlevel equation for the bound states of thequantum well is expressed in terms of the transfer matrix elements.It is found that the electronic transmission exhibitsresonant tunneling peaks at the eigenlevels of the bound states and shifts to the higher energy with increasing the incidentangle.If there are N coupled quantum wells,the resonant modes have N-fold splitting.The peaks of resonant tunnelingcan be controlled by modulating the graphene barriers.
