We report a versatile method to polarize single nuclear spins in diamond, based on optical pumping of a single nitrogen-vacancy (NV) defect and mediated by a level anticrossing in its excited state. A nuclear-spin polarization higher than 98% is achieved at room temperature for the 15N nuclear spin associated with the NV center, corresponding to microK effective nuclear-spin temperature. We the...

The negatively charged nitrogen-vacancy defect in diamond is an important atomic-scale structure that can be used as a qubit in quantum computing and as a marker in biomedical applications. Its usefulness relies on the ability to optically excite electrons between well-defined gap states, which requires a clear and detailed understanding of the relevant states and excitation processes. Here we ...

We present a fiber-coupled diamond-based single photon system. Single nanodiamonds containing nitrogen vacancy defect centers are deposited on a tapered fiber of 273 nanometer in diameter providing a record-high number of 689,000 single photons per second from a defect center in a single-mode fiber. The system can be cooled to cryogenic temperatures and coupled evanescently to other nanophotoni...

The convergence of first-principles supercell calculations for defects in semiconductors is studied with the vacancy in bulk Si as a test case. The ionic relaxations, defect formation energies, and ionization levels are calculated for supercell sizes of up to 216 atomic sites using several k-point meshes in the Brillouin-zone integrations. The energy dispersion, inherent for the deep defect sta...

Ceriuii dioxide doped with y 3 + ions, which is of interest for its ionic conductivity, is here studied by anelastic ~~~ethods. The internal friction peaks observed are analyzed intc peals A , B, C (with Hr = 0.64, 0.71 and 0.78 eV, respectively). Peak A, present at low y3+ concentrations is established to be due to a W pair (V = oxygen-ion vacancy), which is a charged defect conpensated by an ...

Fig. 2 Average binding energy of Pt for 71 different Pt nanostructures on the TiN(100) surface with different concentrations of surface N or Ti vacancies (xv), which refers to the number of vacancies per possible vacancy sites. (a) The average binding energy per Pt atom, as calculated according to eqn (1), versus Pt surface coverage (Y) for up to 3 adlayers (36 Pt atoms) of Pt on the clean TiN(...

Two types of bipolar resistance switching with eightwise and counter eightwise polarities are observed to coexist in Au/SrTiO3/Ti memory cells. These two types of switching can be induced by different defect distributions which are activated by controlling the electric process. The analyses of I-V and C-V data reveal that the resistance switching with eightwise polarity originates from the chan...

Implanted fluorine is observed to behave unusually in silicon, manifesting apparent uphill diffusion and reducing diffusion and enhancing activation of boron. In order to investigate fluorine behavior, we calculate the energy of fluorine defect structures in the framework of density functional theory. In addition to identifying the ground-state configuration and diffusion migration barrier of a...

Hybrid halide perovskites such as methylammonium lead iodide (CH3NH3PbI3) exhibit unusually low free-carrier concentrations despite being processed at low-temperatures from solution. We demonstrate, through quantum mechanical calculations, that an origin of this phenomenon is a prevalence of ionic over electronic disorder in stoichiometric materials. Schottky defect formation provides a mechani...

Results of our shell-model calculations concerning the determination of empirical parameters of inter-ionic potentials and the formation energies of point defects in LiNbO3 are presented. We employed the relaxed fitting method which is particularly appropriate for the modeling of lowsymmetry structure. Attention is paid to guarantee the simulation precision of the parameters who are sensitive f...