Li T S, Lin M F, Chang S C
Department of Electrical Engineering, Kun Shan University, Tainan, Taiwan, Republic of China.
J Phys Condens Matter. 2009 Oct 28;21(43):435302. doi: 10.1088/0953-8984/21/43/435302. Epub 2009 Oct 9.
We investigate theoretically the effects of a nanotube on the graphene nanoribbon Landau level spectrum utilizing the tight-binding model. The addition of a nanotube changes the original dispersionless Landau subbands into distorted parabolic ones, creates additional band-edge states, and modifies the subband spacings. Moreover, the dispersion relations rely sensitively on the nanotube location. The nanotube-ribbon couplings disrupt the Landau wavefunctions and lift their spatial symmetry, which will change the selection rule of optical transitions. The numbers, frequencies and heights of the density of states (DOS) peaks are found to be strongly dependent on the magnetic flux density and the nanotube location. The evolution of the DOS peak with the magnetic flux density is explored. The graphene nanoribbon Landau levels are shown to be modified in an unexpected fashion by the nanotube-ribbon interactions. These predictions can be validated by measuring the spectra of scanning tunneling experiments or magneto-optical experiments, and they are most observable by placing the nanotube at the electron wavefunction localization sites.
我们利用紧束缚模型从理论上研究了纳米管对石墨烯纳米带朗道能级谱的影响。添加纳米管会将原来无色散的朗道子带转变为扭曲的抛物线形子带，产生额外的带边态，并改变子带间距。此外，色散关系对纳米管的位置敏感依赖。纳米管与纳米带的耦合会破坏朗道波函数并提升其空间对称性，这将改变光学跃迁的选择规则。发现态密度（DOS）峰的数量、频率和高度强烈依赖于磁通密度和纳米管位置。探索了DOS峰随磁通密度的演变。结果表明，纳米管与纳米带的相互作用会以意想不到的方式改变石墨烯纳米带的朗道能级。这些预测可以通过测量扫描隧道实验或磁光实验的光谱来验证，并且通过将纳米管放置在电子波函数局域化位置最容易观察到。
