Kuzubov, A. A.*; Kovaleva, E. A.*; Avramov, P. V.*; Kuklin, A. V.*; Mikhaleva, N. S.*; Tomilin, F. N.*; Sakai, Seiji; Entani, Shiro; Matsumoto, Yoshihiro*; Naramoto, Hiroshi*
Journal of Applied Physics, 116(8), p.084309_1 - 084309_4, 2014/08
Avramov, P. V.*; Kuzubov, A. A.*; Sakai, Seiji; Otomo, Manabu*; Entani, Shiro; Matsumoto, Yoshihiro*; Eleseeva, N. S.*; Pomogaev, V. A.*; Naramoto, Hiroshi*
Journal of Porphyrins and Phthalocyanines, 18(7), p.552 - 568, 2014/07
Otomo, Manabu; Yamauchi, Yasushi*; Kuzubov, A. A.*; Eliseeva, N. S.*; Avramov, P.*; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi*; Sakai, Seiji
Applied Physics Letters, 104(5), p.051604_1 - 051604_4, 2014/02
Hexagonal boron nitride (h-BN) is a promising barrier material for graphene spintronics. In this study, spin-polarized metastable de-excitation spectroscopy (SPMDS) is employed to study the spin-dependent electronic structure of monolayer h-BN on Ni(111). The extreme surface sensitivity of SPMDS enables us to elucidate a partial filling of the in-gap states of h-BN without any superposition of Ni 3 signals. The in-gap states are shown to have a considerable spin polarization parallel to the majority spin of Ni. The positive spin polarization is attributed to the - hybridization and the effective spin transfer to the nitrogen atoms at the h-BN/Ni(111) interface.
Avramov, P.; Kuzubov, A. A.*; Sakai, Seiji; Otomo, Manabu; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi*; Eliseeva, N. S.*
Journal of Applied Physics, 112(11), p.114303_1 - 114303_10, 2012/12
Kuzubov, A. A.*; Fedorov, A. S.*; Eliseeva, N. S.*; Tomilin, F. N.*; Avramov, P.; Fedorov, D. G.*
Physical Review B, 85(19), p.195415_1 - 195415_4, 2012/05
Fedorov, A. S.*; Fedorov, D. A.*; Kuzubov, A. A.*; Avramov, P.; Nishimura, Yoshifumi*; Irle, S.*; Witek, H. A.*
Physical Review Letters, 107(17), p.175506_1 - 175506_5, 2011/10
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
Avramov, P.; Kuzubov, A. A.*; Fedorov, A. S.*; Sorokin, P. B.*; Tomilin, F. N.*; Maeda, Yoshihito
Physical Review B, 75(20), p.205427_1 - 205427_8, 2007/05
The atomic and electronic structures of a set of proposed pentagonal thin (1.6 nm in diameter) Si/SiO quantum nanodots (QDs) and nanowires (NWs) with narrow interface, as well as parent metastable Si structures (1.2 nm in diameter), were studied using cluster B3LYP/6-31G and periodic boundary condition (PBC) plane-wave (PW) pseudopotential (PP) local-density approximation methods. The total density of states (TDOS) of the smallest quasispherical QD (Si) corresponds well to the PBC PW PP LDA TDOS of the crystalline Si. The elongated SiQDs and SiNWs demonstrate the metallic nature of the electronic structure. The surface oxidized layer opens the band gap in the TDOS of the Si/SiO species. The top of the valence band and the bottom of conduction band of the particles are formed by the Si core derived states. The theoretical band gap width is determined by the length of the Si/SiO clusters and describes the size confinement effect in the experimental photoluminescence spectra of the silica embedded nanocrystalline Si with high accuracy.
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.
Avramov, P.; Sakai, Seiji; Kuzubov, A. A.*; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi*
no journal, ,
The atomic and electronic structure and potential energy surfaces of 2D extended graphene- and multilayer graphene-based nanocomposites were studied using sophisticated ab initio Long-Corrected DFT (LC-DFT) technique. It was found that LC-DFT scheme coupled with periodic boundary conditions (PBC) allows one to calculate atomic structure of weakly bound multilayer graphenes and graphite with high accuracy. Using PBC and cluster approximations the potential energy surfaces (PES) of migration on and penetration through the carbon lattice of a set of adatoms (carbon, oxygen, nickel) were studied and a number of special points on PESes were found. It was found that LC-DFT scheme predicts the potential energy barriers of adatom migration on graphene surface with high accuracy.