A. L. Pushkarchuk

Theoretical study of hyperfine interactions and optically detected magnetic resonance spectra by simulation of the C291[NV]-H172 diamond cluster hosting nitrogen-vacancy center

Single nitrogen-vacancy (NV) centers in diamond coupled to neighboring nuclear spins are promising candidates for room-temperature applications in quantum information processing, quantum sensing and metrology. Here we report on a systematic density functional theory simulation of hyperfine coupling of the electronic spin of the NV center to individual 13C nuclear spins arbitrarily disposed in the H-terminated C291[NV]-H172 cluster hosting the NV center. For the ‘families’ of equivalent positions of the 13C atom in diamond lattices around the NV center we calculated hyperfine characteristics. For the first time the data are given for a system where the 13C atom is located on the NV center symmetry axis. Electron paramagnetic resonance transitions in the coupled electron–nuclear spin system 14NV-13C are analyzed as a function of the external magnetic field. Previously reported experimental data from Dreau et al (2012 Phys. Rev. B 85 134107) are described using simulated hyperfine coupling parameters.

Kramers-degenerated NV+113C spin systems in diamond: analytical description

Spin systems consisted of single electronic spin S=1 of the NV center and nearby nuclear spins I=1/2 of 13C atoms disposed in diamond lattice near the center can be used as a small register of a quantum computer or as a sensor of a magnetic field. At odd number of nuclear spins eigenvalues of the spin systems at zero external magnetic field are at least twofold degenerated (Kramers degeneration) due to time reversal invariance of the spin Hamiltonian. This degeneracy is lifted only by external magnetic field regardless of the presence of any electric (crystal) field which can also lift the degeneracy thus hindering measurement of the magnetic field. Therefore, the Kramers-degenerated spin systems can be very perspective for measurement of a local magnetic field by the NV-based single-spin quantum magnetometer. Here, we are considering analytically the simplest Kramers-degenerated spin system NV+113C consisting of a single electron spin S=1 of the NV сenter coupled by hyperfine interaction with a single nuclear spin I=1/2 of 13C atom disposed in arbitrary site of diamond lattice. Simple approximate analytical expressions are obtained for eigenvalues and eigenstates of the spin system.

ELASTIC MODULES AND LOW-FREQUENCY OSCILLATIONS OF ISOLATED CARBON NANOTUBES

Institute for Nuclear Problems, BSU, Bobruiskaya 11, 220050 Minsk, Belarus Iinstitute of Physical Organic Chemistry NASB Surganova 13, 220072 Minsk, Belarus alexp@ifoch.bas-net.by Belarusian State University of Informatics and Radioelectronics P. Browka 6, 220013 Minsk, Belarus vadimka@vadimka.com Al-Balqa Applied University, P.O. Box 204,1Amman 11953, Jordan B.I. Stepanov Institute of Physics NASB, Nezavisimosti Ave. 68, 220072 Minsk, Belarus

Structure and magnetic properties of Saturn-shaped fullerenol complexes with ferrocene and nickelocene dicarboxylic acids: DFT simulation

Abstract DFT simulations of the electron and spin structure of fullerenol derivatives C60(OH)24·2Fe(C5H4COOH)2 and C60(OH)24·2Ni(C5H4COOH)2 have shown that these compounds form stable complexes with intermolecular hydrogen bonds. Calculated exchange coupling constants for the last complexes indicate that they can possess ferromagnetic properties. If this is true, then compounds will have a great potential for medical application as drug delivers under the control of external magnetic field.

NEW BIOACTIVE COMPOSITE NANOMATERIALS BASED ON FULLERENE DERIVATIVES

A. G. SOLDATOV, E. M. SHPILEVSKY, V. A. GORANOV, A. L. PUSHKARCHUK, A. A. KHRUTCHINSKY, A. P. NIZOVTSEV, S. Ya. KILIN SSPA “Scientific and Practical Materials Research Center NASB” P. Browka 19, 220072 Minsk, Belarus andreisoldatov@mail.ru A. V. Lykov Institute of the Heat and Mass Transfer NASB P. Browka 15, 220072 Minsk, Belarus Belarusian State Medical University, Dzerzhinski Ave. 83, 220116 Minsk, Belarus Institute of Physical Organic Chemistry NASB, Surganova 13, 220072 Minsk, Belarus Institute for Nuclear Problems, BSU, Bobruiskaya 11, 220050 Minsk, Belarus B. I. Stepanov Institute of Physics NASB, Nezavisimosti Ave. 68, 220072 Minsk, Belarus

Towards scalable quantum computers: nano-design and simulations of quantum register

Quantum information technology (QIT) is extremely fast developing area strongly connected with achievements in modern physics. We present a review of recent achievements in implementation of solid-state scalable quantum processors with special emphasize on diamond-based quantum hardware.

Modeling of electronic and spin structure of single NV centers in nanostructured diamond: influence of nanodiamond surface

Modeling of atomic structure and distribution of spin density for the NV center formed close to the surface (111) of nano-diamond has been carried out using quantum-chemical PM3 and DFT methods. The case is considered where the nitrogen atom of NV center is located in the near-surface atomic layer of a face (111). The relaxation of surface atoms relative to the initial position results in N atom to be shifted from the cluster center parallel to the <111> direction by 0.16Å, and C atoms belonging to the surface layer are also shifted parallel to the <111> direction to the center by 0.18Å. As this takes place, C-C and C-N distances between relaxed atoms decrease and a graphite-like structure is formed on a (111) crystal face. In the structure, the N atom and C atoms nearest to it lay practically in the same plane. The formed CN bond can be considered as one-and-a-half bond. It has been found that unlike the NV center in bulk diamond for which the spin density is located mainly on the carbon atoms, being nearest neighbors to the vacancy of the NV center, in the case of the NV center located in immediate proximity to the surface, there is a redistribution of spin density resulting in its major allocation in three C atoms, the nearest neighbors to the N atom, that form the first atomic layer of a surface (111) of nano-crystal.

DFT MODELING OF STRUCTURAL, ELECTRONIC AND SPIN PROPERTIES OF NICKEL–NITROGEN-CONTAINING (NE8) CENTER IN NANODIAMOND

Quantum chemical simulations have been carried out for the positively charged hydrogen-passivated cluster C33H24N4Ni +1 having a spin-doublet (S=1/2) ground state. After simulation of the relaxed structure of the clusters, calculations of electronic and spin properties were performed. It was shown that the spin density is localized mainly (80 %) at Ni atom and at the six atoms (two carbon and four nitrogen atoms) that are the nearest neighbors to the Ni atom. The isotropic and anisotropic hyperfine coupling constants for Ni isotope (I=3/2), as well as for isotopes N (I=1) and C (I=1/2) of the relaxed lattice were calculated. The found values show that the NE8 center with isotopic nickel can be perspective for future quantum information technological application.