Encontrados 11 documentos, a visualizar página 1 de 2
Low-energy muon [LEM] study of Zn-phthalocyanine and ZnO thin films
Alberto, H. V.; Piroto Duarte, J.; Weidinger, A.; Vilão, R. C.; Gil, J. M.; Ayres de Campos, N.; Fostiropoulos, K.; Prokscha, T.; Suter, A.http://www.sciencedirect.com/science/article/B6TVH-4V2NP2J-14/2/e2844eb805cd79148fe2c51116014ae6
Delayed electron capture and Mu- formation in ZnSe
Vilão, R. C.; Gil, J. M.; Weidinger, A.; Alberto, H. V.; Piroto Duarte, J.; Costa, B. F. O.; Ayres de Campos, N.; Lichti, R. L.; Chow, K. H.http://www.sciencedirect.com/science/article/B6TVH-4V2NP2J-1R/2/ae8c94d2ee3229b6fe7881d93d1a64eb
Detailed hyperfine structure of muoniated radicals in planar phthalocyanines
Piroto Duarte, J.; Vilão, R. C.; Alberto, H. V.; Gil, J. M.; Weidinger, A.; Ayres de Campos, N.http://www.sciencedirect.com/science/article/B6TVH-4V2NP2J-20/2/625b6e64a430f4e722e4eec1de4d54ad
Muonium diffusion dynamics in mercury oxide
Piroto Duarte, J.; Gil, J. M.; Alberto, H. V.; Vilão, R. C.; Weidinger, A.; Ayres de Campos, N.; Cox, S. F. J.; Lord, J. S.; Cottrell, S. P.The diffusion dynamics of the neutral muonium state found in HgO is addressed in this work. We propose a hopping model for the diffusion, and use it to analyse time-domain [mu]SR data. It is found that the diffusion is an incoherent quantum process, with an activation energy of 5.2(2) meV. The analysis also points to the anti-bonding site as the best-suited candidate for the muon's localisation. ; http://www...
Dynamics of muoniated radical states in phthalocyanines
Piroto Duarte, J.; Vilão, R. C.; Alberto, H. V.; Gil, J. M.; Gil, Francisco P. S. C.; Weidinger, A.; Campos, N. Ayres deThis work reports a spectroscopic and spin-dynamics [mu]SR study of the positive muon states formed in the phthalocyanines Zn-Pc, H2-Pc and Cu-Pc. In Zn-Pc and H2-Pc, three distinct muoniated radicals are formed, seen to undergo spin-dynamical processes with charge carriers. Two of the states have very similar hyperfine interaction values, and are believed to be due to muon addition at the outer benzene rings. ...
Muoniated radicals in the organic semiconductor zinc-phthalocyanine
Duarte, J. Piroto; Vilão, R. C.; Gil, J. M.; Alberto, H. V.; Ayres de Campos, N.; Weidinger, A.[mu]SR experiments were conducted on the organic semiconductor zinc-phthalocyanine (Zn-Pc) in order to identify and characterize the muon states in this material. Transverse-field experiments at 0.5 mT reveal the existence of paramagnetic muon states in Zn-Pc, with the formation probability of nearly 100%. Two different muoniated radicals were detected, with hyperfine parameters of 127 and 142 MHz; muonium is t...
Muon diffusion and trapping in chalcopyrite semiconductors
Vilão, R. C.; Gil, J. M.; Alberto, H. V.; Duarte, J. Piroto; Campos, N. Ayres de; Weidinger, A.; Yakushev, M. V.; Cox, S. F. J.The diffusion parameters of diamagnetic muons in chalcopyrites CuInSe2, CuInS2, CuInTe2, CuGaTe2 and (Ag0.25Cu0.75)InSe2 were obtained by [mu]SR methods. The variations among the different compositions were found to validate the anion-antibonding localization model. The application of a two-state model to the zero-field data revealed muon trapping by defects. The dipolar width at the trap and the number of jump...
Muon and hydrogen states in II-VI semiconductor compounds. A muSR study
Weidinger, A.; Alberto, H. V.; Gil, J. M.; Vilão, R. C.; Duarte, J. Piroto; Campos, N. Ayres deAdditional hydrogen in II-VI semiconductors may occur in two different configurations, either bound to the anion in a position along the bond direction, or at an open interstitial site surrounded by four cations. The electronic character of these states is very different: the bound hydrogen forms a donor with an extended electronic wave function, whereas the interstitial hydrogen is acceptor-like and has an alm...
Probing the shallow-donor muonium wave function in ZnO and CdS via transferred ...
Lord, J. S.; Cottrell, S. P.; King, P. J. C.; Alberto, H. V.; Ayres de Campos, N.; Gil, J. M.; Duarte, J. Piroto; Vilão, R. C.; Lichti, R. L.The assignment of muon spin rotation spectra to muonium counterparts of hydrogen shallow-donor states is reviewed in four II-VI widegap semiconductors, CdS, CdSe, CdTe and ZnO. The existence of extended electronic orbitals is argued from the muon-electron hyperfine parameters and supported by the new muon spin repolarization data for CdS and ZnO, characterizing the superhyperfine parameters on the sparse Cd and...
Shallow-level muonium centre in CdS
Gil, J. M.; Alberto, H. V.; Vilão, R. C.; Duarte, J. Piroto; Mendes, P. J.; Campos, N. Ayres de; Weidinger, A.; Krauser, J.; Niedermayer, Ch.A new type of muonium defect centre has been observed in undoped CdS at low temperatures (T<20Â K). The hyperfine parameters are A[short parallel]=335 (7)Â kHz and A[perpendicular]=199 (6)Â kHz (approximately 10-4 of the vacuum value) with the symmetry axis along the Cd-S bond direction. The disappearance of the centre at around 20Â K is in agreement with the binding energy of a shallow centre. The extremely we...
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