Coherent transport in Y-junction graphene waveguide. (10th October 2018)

• Record Type: Journal Article
• Authors: Mosallanejad, Vahid; Chiu, Kuei-Lin; Guo, Guo-Ping
• Is Part Of: Journal of physics. Volume 30:Number 44(2018)
• Publication Date: 2018-10-10
• Subjects: electron waveguides -- graphene -- non-equilibrium Greens function (NEGF) -- conductance quantization; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aae09d
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We performed a series of theoretical transport studies on Y-branch electron waveguides which are embedded in mid-size armchair graphene nanoribbons. Non-equilibrium Green's function with different approximations of tight-binding Hamiltonian has been employed. Using the first nearest hopping approximation, we observed very pronounced conductance quantization, the structure of which depends on geometrical design and shows a spacing of 4 e 2 / h, indicating the existence of valley degree of freedom. Moreover, by incorporating the third nearest approximation, we observed seminal plateaus deviated from multiples of 4 e 2 / h conductance, suggesting the lift of valley degeneracy. Finally, Quasi-one dimensional band structure calculations have been performed to study the availability of energy channels and the role of the major geometrical parameters on the transport.