Low-Energy Coherent Transport in Metallic Carbon Nanotube Junctions

We study the low-energy electronic properties of a junction made of two crossed metallic carbon nanotubes of general chiralities. We derive a tight-binding tunneling matrix element that couples low-energy states on the two tubes, which allows us to calculate the contact conductance of the junction. We find that the intrinsic asymmetries of the junction cause the forwardand backward-hopping probabilities from one tube to another to be different. This defines a zero-field Hall conductance for the junction, which we find to scale inversely with the junction contact conductance. Through a systematic study of the dependence of the junction conductance on different junction parameters, we find that the crossing angle is the dominant factor that determines the magnitude of the conductance. Disciplines Physical Sciences and Mathematics | Physics Comments Suggested Citation: A.A. Maarouf and E.J. Mele. (2011). "Low-energy coherent transport in metallic carbon nanotube junctions." Physical Review B. 83, 045402. © 2011 The American Physical Society http://dx.doi.org/10.1103/PhysRevB.83.045402 This journal article is available at ScholarlyCommons: http://repository.upenn.edu/physics_papers/88 PHYSICAL REVIEW B 83, 045402 (2011) Low-energy coherent transport in metallic carbon nanotube junctions A. A. Maarouf1,2 and E. J. Mele3 1IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA 2Egypt Nanotechnology Research Center, Smart Village, Building 121, Giza 12577, Egypt 3Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA (Received 22 July 2010; published 3 January 2011) We study the low-energy electronic properties of a junction made of two crossed metallic carbon nanotubes of general chiralities. We derive a tight-binding tunneling matrix element that couples low-energy states on the two tubes, which allows us to calculate the contact conductance of the junction. We find that the intrinsic asymmetries of the junction cause the forwardand backward-hopping probabilities from one tube to another to be different. This defines a zero-field Hall conductance for the junction, which we find to scale inversely with the junction contact conductance. Through a systematic study of the dependence of the junction conductance on different junction parameters, we find that the crossing angle is the dominant factor that determines the magnitude of the conductance. DOI: 10.1103/PhysRevB.83.045402 PACS number(s): 73.63.Fg, 73.23.Ad, 72.80.Rj, 73.40.Gk