ﺿﺮﯾﺐ ﻋﺒﻮر ﯾﮏ ﻧﺎﻧﻮﻧﻮار ﮔﺮاﻓﻦ ﻧﺮدﺑﺎﻧﯽ ﺷﮑﻞ ﺑﻠﻨﺪ ﻣﺘﺼﻞ ﺑﻪ ﭼﻨﺪ ﺑﻨﺰن اﺿﺎﻓﯽ

Transmission Coefficient of a Lengthy Ladder-Like Graphene Nanoribbin Connected to Some Additional Benzene Rings

در اﯾﻦ ﻣﻘﺎﻟﻪ ﺑﻪ ﺑﺮرﺳﯽ ﺧﻮاص ﺗﺮاﺑﺮد اﻟﮑﺘﺮوﻧﯽ ﭘﯿﮑﺮﺑﻨﺪيﻫﺎي ﻣﺘﻔﺎوت ﯾﮏ ﻧﺎﻧﻮﻧﻮار ﻧﺮدﺑﺎﻧﯽ ﺷﮑﻞ ﻧﺎﻣﺘﻨﺎﻫﯽ ﮐﻪ ﭼﻨﺪ ﺣﻠﻘﻪ ﺑﻨﺰن در ﻗﺴﻤﺖ ﮐﻮﭼﮑﯽ از آن اﺿﺎﻓﻪ ﺷﺪه اﺳﺖ، ﻣﯽﭘﺮدازﯾﻢ. ﺑﺮاي اﯾﻦ ﻣﻨﻈﻮر از روش ﺗﺎﺑﻊ ﮔﺮﯾﻦ ﺗﺮازﻣﻨﺪي در رﻫﯿﺎﻓﺖ ﺗﻨﮕﺎﺑﺴﺖ و ﺗﻘﺮﯾﺐ ﻧﺰدﯾﮏﺗﺮﯾﻦ ﻫﻤﺴﺎﯾﻪ اﺳﺘﻔﺎده ﻣﯽﮐﻨﯿﻢ. اﺑﺘﺪا ﺑﺎ ﻣﻌﺮﻓﯽ ﯾﮏ ﺗﺒﺪﯾﻞ ﻣﺘﻌﺎﻣﺪ، ﻫﺎﻣﯿﻠﺘﻮﻧﯽ ﻧﺎﻧﻮ ﻧﻮار در راﺳﺘﺎي ﺳﻄﺢ ﻣﻘﻄﻊ را ﻗﻄﺮي ﻣﯽﮐﻨﯿﻢ. در واﻗﻊ، ﻫﺎﻣﯿﻠﺘﻮﻧﯽ ﺳﺎﻣﺎﻧﻪ ﻣﻮرد ﻧﻈﺮ را ﺑﺎ اﺳﺘﻔﺎده از اﯾﻦ ﺗﺒﺪﯾﻞ ﺑﻪ ﮔﻮﻧﻪاي ﺗﻐﯿﯿﺮ ﻣﯽدﻫﯿﻢ ﮐﻪ ﻫﺎﻣﯿﻠﺘﻮﻧﯽ ﻗﺴﻤﺖﻫﺎي اﯾﺪه آل آن ﻣﻌﺎدل ﻫﺎﻣﯿﻠﺘﻮﻧﯽ دو زﻧﺠﯿﺮه ي ﺳﺎده ﺑﺎﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ ﺣﻀﻮر ﺣﻠﻘﻪﻫﺎي اﺿﺎﻓﯽ، ﺑﺎﻋﺚ ﮐﺎﻫﺶ رﺳﺎﻧﺶ ﺷﺪه و در ﺑﻌﻀﯽ ﻣﻮارد، درهﻫﺎي ﺿﺪ ﺗﺸﺪﯾﺪي در ﻃﯿﻒ ﺿﺮﯾﺐ ﻋﺒﻮر اﻟﮑﺘﺮوﻧﯽ اﯾﺠﺎد ﻣﯽﮐﻨﺪ. رﺳﺎﻧﺶ اﻟﮑﺘﺮوﻧﯽ ﭘﯿﮑﺮﺑﻨﺪيﻫﺎي ﻣﺨﺘﻠﻒ ﮐﻪ از ﺟﺎﺑﺠﺎﯾﯽ ﻣﮑﺎن ﺣﻠﻘﻪﻫﺎي اﺿﺎﻓﯽ ﺷﮑﻞ ﻣﯽﮔﯿﺮﻧﺪ، ﻣﻄﺎﻟﻌﻪ و ﻣﻘﺎﯾﺴﻪ ﺷﺪه اﺳﺖ. ﺑﺨﺼﻮص ﻣﻘﺪار ﺿﺮﯾﺐ ﻋﺒﻮر در اﻧﺮژي ﻓﺮﻣﯽ در ﭘﯿﮑﺮﺑﻨﺪيﻫﺎي ﻣﺘﻔﺎوت را ﻣﻮرد ﺗﻮﺟﻪ ﻗﺮار داده اﯾﻢ. ﻣﺪل اراﺋﻪ ﺷﺪه ﺑﺮاي ﻫﺮ ﺳﺎﺧﺘﺎر اﺧﺘﯿﺎري ﻻﻧﻪ زﻧﺒﻮري ﺑﻪ ﻋﻨﻮان ﺳﺎﻣﺎﻧﻪ ﻣﺮﮐﺰي ﮐﻪ ﺑﯿﻦ دو ﻧﺎﻧﻮ ﻧﻮار ﮔﺮاﻓﻦ ﻧﺮدﺑﺎﻧﯽ ﺷﮑﻞ ﻗﺮار ﮔﯿﺮد، ﻗﺎﺑﻞ ﺗﻌﻤﯿﻢ اﺳﺖ.

In this paper, we consider the electronic transport properties of different configurations of a ladder-like nanoribbon which is connected to some benzene rings in its small part. To this end, we use the equilibrium Green’s function method within the tight-binding approach and the nearest neighbor approximation. We first introduce a unitary transformation matrix in order to diagonalize the matrix Hamiltonian of the nanoribbon in its cross-section direction. In fact, we rewrite the Hamiltonian of the system in a way that the Hamiltonian of the ideal parts converts to the Hamiltonian of two simple chains. The results show that the existence of the extra rings makes the conductance decreasing and creation of some anti-resonance deeps in the transmission coefficient spectra for some cases. The electronic transmission coefficients of the different configurations which are constructed by position variation of extra rings are studied and compared. Particularly, the value of the electronic conductance in the Fermi energy for different configurations is taken into the investigation. The model can be extended for any arbitrary honeycomb structure of the center part which is connected to two ladder-like nanoribbon leads.