The di-interstitial in graphite

Di-interstitial defects appear to play a key role in the microscopic understanding of radiation-induced damage in graphite. Their formation has been invoked as both one of the main causes of dimensional change and as an energy releasing step in annealing cryogenic radiation-induced damage. In the present work, first principles calculations are employed to examine several models for these defects. Two of the structures possess nearly equal energy, yet take very different forms. The results suggest that di-interstitial defects cannot play the principal role in radiation damage that has been assigned to them. The possibility that one of the structures may exhibit ferromagnetism is also investigated.

[1]  E. Wigner.  Theoretical Physics in the Metallurgical Laboratory of Chicago , 1946 .

[2]  S. Goedecker,et al.  Relativistic separable dual-space Gaussian pseudopotentials from H to Rn , 1998, cond-mat/9803286.

[3]  S. Iijima,et al.  In situ observation of thermal relaxation of interstitial-vacancy pair defects in a graphite gap. , 2005, Physical review letters.

[4]  Induced magnetic ordering by proton irradiation in graphite. , 2003, Physical review letters.

[5]  R. M. Mayer,et al.  THE INFLUENCE OF BORON ON THE CLUSTERING OF RADIATION DAMAGE IN GRAPHITE. II. NUCLEATION OF INTERSTITIAL LOOPS. , 1969 .

[6]  Stuart A. Rice,et al.  Graphite and Its Crystal Compounds , 1961 .

[7]  S. Reich,et al.  Defect energies of graphite: Density-functional calculations , 2005 .

[8]  S. Amelinckx,et al.  Dislocation Loops Due to Quenched-in Point Defects in Graphite , 1960 .

[9]  A. Krasheninnikov,et al.  Magnetic properties and diffusion of adatoms on a graphene sheet. , 2003, Physical review letters.

[10]  Zhang,et al.  Dopant and defect energetics: Si in GaAs. , 1993, Physical review. B, Condensed matter.

[11]  D. G. Martin,et al.  The effect of irradiation temperature on the scattering of long wavelength neutrons by defects in neutron-irradiated graphite , 1967 .

[12]  R. Nieminen,et al.  Ab initio study of fully relaxed divacancies in GaAs. , 1996, Physical review. B, Condensed matter.

[13]  Paxton,et al.  High-precision sampling for Brillouin-zone integration in metals. , 1989, Physical review. B, Condensed matter.

[14]  Wang,et al.  Accurate and simple analytic representation of the electron-gas correlation energy. , 1992, Physical review. B, Condensed matter.

[15]  Niwase.  Irradiation-induced amorphization of graphite. , 1995, Physical review. B, Condensed matter.

[16]  R. Nieminen,et al.  Ab initio study of oxygen point defects in GaAs, GaN, and AlN. , 1996, Physical review. B, Condensed matter.

[17]  Gareth B Neighbour,et al.  Modelling of dimensional changes in irradiated nuclear graphites , 2000 .

[18]  Jörg Neugebauer,et al.  First-principles studies of beryllium doping of GaN , 2001 .

[19]  Zhang,et al.  Chemical potential dependence of defect formation energies in GaAs: Application to Ga self-diffusion. , 1991, Physical review letters.

[20]  Susan B. Sinnott,et al.  Combined computational and experimental study of Ar beam induced defect formation in graphite , 2007 .

[21]  Patrick R. Briddon,et al.  Rapid iterative method for electronic-structure eigenproblems using localised basis functions , 2008, Comput. Phys. Commun..

[22]  F. Banhart,et al.  Irradiation effects in carbon nanostructures , 1999 .

[23]  H. Monkhorst,et al.  SPECIAL POINTS FOR BRILLOUIN-ZONE INTEGRATIONS , 1976 .

[24]  H. Maeta,et al.  c-Axis Spacing Changes in Pyrolytic Graphite after Neutron Irradiation at 5 K , 1975 .

[25]  R. Telling,et al.  Metastable Frenkel pair defect in graphite: source of Wigner energy? , 2003, Physical Review Letters.

[26]  Yuchen Ma,et al.  Irradiation-Induced Magnetism in Graphite : A Density Functional Study , 2004 .

[27]  D. B. Fischbach.  DIAMAGNETIC SUSCEPTIBILITY OF PYROLYTIC GRAPHITE , 1961 .

[28]  Robert Jones,et al.  LDA Calculations Using a Basis of Gaussian Orbitals , 2000 .

[29]  R. Faccio,et al.  Magnetism induced by single carbon vacancies in a three-dimensional graphitic network , 2008 .

[30]  T. Iwata.  Fine structure of Wigner energy release spectrum in neutron irradiated graphite , 1985 .

[31]  R. Telling,et al.  Wigner defects bridge the graphite gap , 2003, Nature materials.

[32]  B. Luther-Davies,et al.  Unconventional Magnetism in All-Carbon Nanofoam , 2004 .