Novel Electronic States from Nodal-adsorbates in Metallic Armchair Graphene Nanoribbon

• Main Authors: Hsu, Chun-Yu, 許峻瑜
• Other Authors: 朱仲夏
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/72063362212121969373

碩士 === 國立交通大學 === 電子物理系所 === 104 === An adsorbate located on a nodal site of a metallic armchair graphene nanoribbon (AGNR) forms a bound state [1]. The bound state wave function exhibits anisotropic decaying behavior. It is then of interest to explore the effect of this spatial behavior on the bound state that will form between two or more nodal adsorbates. Specifically, we consider the case of two nodal adsorbates for the establishment of a two-basis approximation (2BA) in the calculation of the bound states formed from the nodal adsorbate pair. The two basis are the bound state wave function of the individual nodal adsorbate. This 2BA scheme provides us a transparent way to understand the bound state energy of the nodal adsorbate pair in light of the site-dependent sign of the basis wave function. Issues concerning the A/B-type and the nodal-type of the 2 adsorbates and the connection to adsorbate recognition will be studied. Effects on the conductance will also be studied. Furthermore, cases of nodal adsorbate chain, with nodal adsorbates line up periodically along a nodal line of the AGNR, are studied. Depending on whether only the A (or B) site or both A and B sites involved in the nodal adsorbate chain, one or two dispersive energy bands, respectively, are formed in the energy of the AGNR gapless sub-band. Interestingly, the gapless sub-band remain intact but the gapped sub-bands are modified by the presence of the nodal-adsorbate chain. Our two-basis approximation is extended to describe nodal-adsorbate chain energy band of large enough adsorbate separation.