Characteristic muonium (?+ meson) states in single-crystal silicon

Barsov, S.; Getalov, A. L.; Gordeev, V. A.; Konopleva, R.F.; Kruglov, S. P.; Кудинов, В. И.; Kuzmin, L. A.; Mikirtychyants, S.; Minaichev, E.V.; Myasishcheva, G. G.; Obukhov, Yu. V.; Savel'ev, G.I.; Firsov, V.G.; Shcherbakov, G. V.

doi:10.1007/bf01037505

Cited by 3 publications

(2 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Different calculational methods seem to disagree on whether the interaction with cage atoms is bonding or antibonding but spin density maps computed by Maric et al (1990) show how effective this transfer is, reaction (9) proceeding almost to completion if the muon occupies the antibonding site, a shallow local minimum of the potential energy surface. (Almost certainly, this was the broken-bond model for anomalous muonium envisaged by Barsov et al (1981); here it is used to explain a more modest reduction of hyperfine constant for normal muonium, as zero-point energy delocalizes it around the cage, from the central T site towards the four AB sites.) Luchsinger et al (1997) likewise predict a reduction of contact interaction as the muon moves from T towards AB, and also towards the hexagonal site.…”

Section: Spin-lattice Interactionsmentioning

confidence: 94%

“…Thus Estle (1981) and Blazey et al (1981Blazey et al ( , 1983 had also manipulated the Mu * hyperfine parameters for crystalline Si and Ge into isotropic (contact) and traceless dipolar terms, as in equations ( 7) and ( 8), but made the opposite choice of signs, leading them to propose the so-called hexagonal site-this is the centre of the puckered ring of six atoms leading from one tetrahedral cage to another, marked 'Hex' in figure 4 20 . In fact, Barsov et al (1981) came closest with their notion of muonium breaking a Si-Si bond, attaching to one Si atom and leaving a dangling bond on the other. Their brief description appears to imply the antibonding site, muonium attacking the bond end-on, so to speak 21 , but Mjakenkaya et al (1988) describe a version with the muon located between the two atoms of the broken bond: these authors insist that only the Si atom carrying the whole unpaired spin is displaced, into the so-called semivacancy 20 This was also the site favoured by on symmetry grounds alone, referred to in the English translations as the octapore.…”

Section: Metastability: Cage-centred and Bond-centred Muoniummentioning

confidence: 99%

See 1 more Smart Citation

Muonium as a model for interstitial hydrogen in the semiconducting and semimetallic elements

2009

View full text Add to dashboard Cite

Although the interstitial hydrogen atom would seem to be one of the simplest defect centres in any lattice, its solid state chemistry is in fact unknown in many materials, not least amongst the elements. In semiconductors, the realization that hydrogen can profoundly influence electronic properties even as a trace impurity has prompted its study by all available means-but still only in the functionally important or potentially important materials-for the elements, Si, Ge and diamond. Even here, it was not studies of hydrogen itself but of its pseudo-isotope, muonium, that first provided the much needed microscopic pictures of crystallographic site and local electronic structure-now comprehensively confirmed by ab initio computation and such data as exists for monatomic, interstitial hydrogen centres in Si. Muonium can be formed in a variety of neutral paramagnetic states when positive muons are implanted into non-metals. The simple trapped atom is commonly only metastable. It coexists with or reacts to give defect centres with the unpaired electron in somewhat more extended orbitals. Indications of complete delocalization into effective mass states are discussed for B, α-Sn, Bi and even Ge, but otherwise all the muonium centres seen in the elemental semiconductors are deep and relatively compact. These are revealed, distinguished and characterized by µSR spectroscopy-muon spin rotation and resonance informing on sites and spin-density distributions, muon spin relaxation on motional dynamics and charge-state transitions.This Report documents the progress of µSR studies for all the semiconductors and semimetals of the p-block elements, Groups III-VI of the Periodic Table . The striking spectra and originally unanticipated results for Group IV are for the most part well known but deserve summarizing and updating; the sheer diversity of muonium states found is still remarkable, especially in carbon allotropes. The interplay of crystallographic site and charge state in Si and Ge at high temperatures, or under illumination, reflects the capture and loss of charge carriers that should model the electrical activity of monatomic hydrogen but still challenges theoretical descriptions. Spin-flip scattering of conduction electrons by the paramagnetic centres is revealed in heavily doped n-type material, as well as some modification of the local electronic structures. The corresponding spectroscopy for the solid elements of Groups III, V and VI is rather less well known and is reviewed here for the first time; a good deal of previously unpublished data is also included. Theoretical expectations and computational modelling are sparse, here. Recent results for B suggest a relatively shallow centre with molecular character; P and As show deeper quasi-atomic states, but still with substantial overlap of spin density onto surrounding host atoms. Particular attention is paid to the chalcogens. Muonium centres in Te show charge-state transitions already around room temperature; the identification of those in S and Se has been compli...

show abstract

Section: Spin-lattice Interactionsmentioning

confidence: 94%