Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Boron and Nitrogen Doped Single walled Carbon Nanotubes as Possible Dilute Magnetic Semiconductors | Nanoscale Res Lett 2007 2 447-449 DOI s11671-007-9082-4 NANO EXPRESS Boron and Nitrogen Doped Single walled Carbon Nanotubes as Possible Dilute Magnetic Semiconductors Frank J. Owens Received 31 May 2007 Accepted 19 July 2007 Published online 10 August 2007 to the authors 2007 Abstract The structure of single walled armchair and zig-zag carbon nanotubes having 70 atoms and two carbons replaced by boron or nitrogen is obtained at minium energy using HF 6-31G molecular orbital theory. The calculations show that the ground state of the zig-zag tubes is a triplet state while for the armchair tubes it is a singlet. In the zig-zag tubes the density of states at the Fermi level is greater for the spin down states compared to the spin up state indicating that the doped tubes could be ferromagnetic. Keywords Carbon nanotubes Dilute magnetic semiconductors Boron Nitrogen Introduction The switching elements in computers metal oxide silicon field effect transistors involve turning of and on the flow of current in the form of holes and electrons. On the other hand the storage of data employs a separate material consisting of nanosized magnetic materials. There is considerable interest in combining storage of information and switching into one material by developing magnetic semiconductors referred to as dilute magnetic semiconductors. There have been a number of reports presenting evidence that semiconductors such as F. J. Owens El Armament Research Development and Engineering Ctr. Picatinny NJ 07806 USA e-mail fowens@ F. J. Owens Department of Physics Hunter College CUNY 959 Park Ave New York NY 10021 USA GaP GaN GaAs and ZnO when doped with Cu2 and Mn2 are ferromagnetic 1-5 . An alternate approach to developing magnetic semiconductors might be to explore the possibility of making single walled carbon nanotubes SWNTs ferromagnetic by appropriate doping of other atoms for carbon on the walls of the tube. SWNTs can be viewed as sheets of graphene rolled into
