Contracted interlayer distance in graphene/sapphire heterostructure

Entani, Shiro; Antipina, L. Y.*; Avramov, P.*; Otomo, Manabu*; Matsumoto, Yoshihiro*; Hirao, Norie; Shimoyama, Iwao; Naramoto, Hiroshi*; Baba, Yuji; Sorokin, P. B.*; et al.

Nano Research, 8(5), p.1535 - 1545, 2015/05

https://doi.org/10.1007/s12274-014-0640-7

Intrinsic edge asymmetry in narrow zigzag hexagonal heteroatomic nanoribbons causes their subtle uniform curvature

Avramov, P.; Fedorov, D. G.*; Sorokin, P. B.*; Sakai, Seiji; Entani, Shiro; Otomo, Manabu; Matsumoto, Yoshihiro; Naramoto, Hiroshi*

Journal of Physical Chemistry Letters (Internet), 3(15), p.2003 - 2008, 2012/08

https://doi.org/10.1021/jz300625t

Influence of size effect on the electronic and elastic properties of diamond films with nanometer thickness

Chernozatonskii, L. A.*; Sorokin, P. B.*; Kuzubov, A. A.*; Sorokin, B. P.*; Kvashnin, A. G.*; Kvashnin, D. G.*; Avramov, P.; Yakobson, B. I.*

Journal of Physical Chemistry C, 115(1), p.132 - 136, 2011/01

https://doi.org/10.1021/jp1080687

Multiterminal nanowire junctions of silicon; A Theoretical prediction of atomic structure and electronic properties

Avramov, P.; Chernozatonskii, L. A.*; Sorokin, P. B.*; Gordon, M. S.*

Nano Letters, 7(7), p.2063 - 2067, 2007/07

https://doi.org/10.1021/nl070973y

Using an empirical scheme, the atomic structure of a new exotic class of silicon nanoclusters was elaborated upon the central icosahedral core (Si-IC) and pentagonal petals (Si-PP) growing from Si-IC vertexes. It was shown that Si-IC/Si-PP interface formation is energetically preferable. Some experimental observations of silicon nanostructures can be explained by the presence of the proposed objects. The extended Huckel theory electronic structure calculations demonstrate an ability of the proposed objects to act as nanoscale tunnel junctions.

Band-gap unification of partially Si-substituted single-wall carbon nanotubes

Avramov, P.; Sorokin, P. B.*; Fedorov, A. S.*; Fedorov, D. G.*; Maeda, Yoshihito

Physical Review B, 74(24), p.245417_1 - 245417_8, 2006/12

https://doi.org/10.1103/PhysRevB.74.245417

The atomic and electronic structure of a set of pristine single wall SiC nanotubes as well as Si-substituted carbon nanotubes and a SiC sheet was studied by the LDA plane wave band structure calculations. Consecutive substitution of carbon atoms by Si leads to a gap opening in the energetic spectrum of the metallic (8,8) SWCNT with approximately quadratic dependence of the band gap upon the Si concentration. The same substitution for the semiconductor (10,0) SWCNT results in a band gap minimum (0.27 eV) at 25% of Si concentration. In the Si concentration region of 12-18%, both types of nanotubes have less than 0.5 eV direct band gaps at the - point. The calculation of the chiral (8,2) SWSiCNT system gives a similar (0.6 eV) direct band gap. The regular distribution of Si atoms in the atomic lattice is by 0.1 eV/atom energetically preferable in comparison with a random distribution. Time dependent DFT calculations showed that the silicon substitution sufficiently increases (roughly by one order of magnitude) the total probability of optical transitions in the near infrared region, which is caused by the opening of the direct band gap in metallic SWCNTs, the unification of the nature and energy of band gaps of all SWCNT species, the large values of Si3Si3 radial integrals and participation of Si3 states in chemical bonding in both valence and conductance bands.

Materials design and characterization of nano-carbons for spintronic applications

Sakai, Seiji; Matsumoto, Yoshihiro; Entani, Shiro; Otomo, Manabu; Sorokin, B. P.*; Avramov, P.; Naramoto, Hiroshi*; Sakuraba, Yuya*; Takanashi, Koki

no journal, , 

no abstracts in English

Atomic structure determination of the graphene/sapphire interface by normal incident X-ay standing wave spectroscopy

Entani, Shiro; Sorokin, B. P.*; Avramov, P.; Otomo, Manabu; Matsumoto, Yoshihiro; Narita, Ayumi; Hirao, Norie; Shimoyama, Iwao; Sekiguchi, Tetsuhiro; Naramoto, Hiroshi*; et al.

no journal, , 

Structure and electronic properties of Si/SiO clusters, nanoparticles and nanowires

Avramov, P.; Kuzubov, A. A.*; Fedorov, A. A.*; Tomilin, F. N.*; Sorokin, P. B.*

no journal, , 

The small SiO clusters are the precursors of the Si/SiO objects and play a key role in their synthesis. The reaction paths for formation and isomerization of a set of silica SiO (m=2, 3, n=1-5) nanoclusters have been investigated using second order pertubation theory (MP2) with the 6-31G(d) basis set. Although transition states have been located for many isomerization reactions, only for SiO and SiO some transition states have been found for the formation of a cluster from the separated reactants. The electronic structure calculations of the Si and Si/SiO quantum dots and nanowires have been performed using the DFT B3LYP/6-31G and PBC LDA PP PW approximations. The polycrystalline nature of the Si nanowires and Si quantum dots leads to the metallic state of all species. The oxidized SiO surface leads to stabilization of the atomic structure of all Si/SiO nanowires and to the opening of the semiconductor gap (1.4eV) in the TDOS. The top of the valence band and the bottom of the conductivity band of the Si/SiO nanoobjects are formed manly by Si p-states.