Strongly correlated impurity band superconductivity in diamond: X-ray spectroscopic evidence

Nesládek, Miloš; Mareš, Jiřı́ J.; Tromson, D.; Mer, C.; Bergonzo, P.; Hubı́k, P.; Krištofik, J.

doi:10.1016/j.stam.2006.04.010

Cited by 24 publications

(5 citation statements)

References 21 publications

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Section: ) Phonon-mediated or Correlation-driven Mechanisms ?mentioning

confidence: 99%

“…Indeed, when the Fermi level is located in a narrow electronic band, the so-called resonant valence band (RVB) model can explain a superconducting transition with a specific pairing mechanism, alternative to the standard phonon mediation. Besides the case of doped diamond [39] , such a correlation-driven mechanism has for instance been proposed in the case of doped fullerenes [40,41] .Ab initio calculations within density functional theory performed on highly-doped diamond [42][43][44][45][46][47] , silicon [4,48] and silicon carbide [49] consistently led to the picture that in the percent doping range, the Fermi levels lies a few tenths of an eV below the top of the valence bands. These results where obtained either within the virtual crystal approximation (VCA) [42][43][44] or supercell (SC) [45][46][47] calculations for various cell geometries and doping concentrations.…”

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confidence: 96%

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Superconducting group-IV semiconductors

et al. 2009

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We present recent achievements and predictions in the field of doping-induced superconductivity in column IV-based covalent semiconductors, with a focus on Bdoped diamond and silicon. Despite the amount of experimental and theoretical work produced over the last four years, many open questions and puzzling results remain to be clarified. The nature of the coupling (electronic correlation and/or phonon-mediated), the relationship between the doping concentration and the critical temperature (T C ), which determines the prospects for higher transition temperatures, as well as the influence of disorder and dopant homogeneity, are debated issues that will determine the future of the field. We suggest that innovative superconducting devices, combining specific properties of diamond or silicon, and the maturity of semiconductor-based technologies, will soon be developed. 1) IntroductionIt was probably the discovery of a superconducting transition around 40 K in the rather simple MgB 2 compound [1] that revived the interest for a specific class of superconducting materials, belonging to the so-called covalent metals [2] . These superconducting covalent systems (see box 1), including B-doped diamond [3] , silicon [4] , and silicon carbide [5,6] , Ba-doped silicon clathrates [7,8] , alkali-doped fullerenes [9,10] and the CaC 6 or YbC 6 intercalated graphites [11,12] , share the specificity of involving at least one relatively light element and of preserving strongly directional covalent bonds in their metallic state. The implications of this covalent character are important in superconductors in which Cooper pairs are coupled through phonons. The use of perturbation theory to study the renormalisation of the electron-electron repulsion by the electron-phonon interaction leads to the so-called Eliashberg equations [13] and to the celebrated McMillan formula [13] relating, in an approximate way, the superconducting transition temperature T C to an average phonon frequency ω ln , the electron-phonon coupling parameter λ ep and the screened and retarded Coulomb repulsion parameter µ*: Clearly, low atomic masses lead to high frequency phonon modes, which may enhance the ω ln prefactor and thus T C . This is the basis of the so-called isotope effect. Furthermore, strong covalent bonding will lead both to large phonon frequencies and a large electron-phonon coupling potential V ep =λ ep /N(E F ), with N(E F ) the density of states at the Fermi level, also contributing to enhance T C . Even within a phonon-mediated coupling scenario, these criteria do not necessarily warrant a large T C since increasing λ ep may also lead to a lattice instability, and a large electron-phonon potential V ep may be impaired by a low density N(E F ). However, these simple considerations, as well as more elaborate surveys and predictions of a larger T C [14][15][16] , have provided much incentive to study this class of materials.The most familiar covalent systems are certainly diamond and silicon. The former can be considered as the prototype insula...

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Section: ) Phonon-mediated or Correlation-driven Mechanisms ?mentioning

confidence: 99%

mentioning

confidence: 96%

Superconducting group-IV semiconductors

et al. 2009

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“…Thus, it was pointed out that superconductivity in BDD is due to a phonon mediated pairing mechanism. An alternative theory proposed by Baskaran suggests the existence of resonant valence bond (RVB)type mechanism in the rigid impurity band of superconducting BDD [9,10].…”

Section: Introductionmentioning

confidence: 99%

Flux pinning and improved critical current density in superconducting boron doped diamond films

2018

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The ability to carry transport current in a magnetic field is the most important aspect of a superconductor. We present a detailed analysis of the upper critical field (H c2 (0)) and vortex dynamics in superconducting boron doped diamond (BDD) films. H c2 (0) measured on the samples of different doping levels revealed a high critical field of up to 7.3 T. Pinning potential U 0 , estimated using thermally activated flux-flow (TAFF) model shows that U 0 is of the order of 10 2 K. Self-field critical current density (J c ) estimated for the superconducting BDD films showed large J c ∼10 7 A/cm 2 due to enhanced flux trapping.

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“…Boron being smaller than carbon atom easily gets incorporated at substitutional site during CVD growth [68]. Boron doping beyond a critical hole concentration n h > 3 × 10 21 cm −3 makes diamond superconducting [10,[69][70][71]. Till date, homoepitaxial (111) films have demonstrated the highest offset superconducting transition temperature of up to T c,zero = 10.2 K [72][73][74].…”

Section: P-type Diamond: Boron Dopingmentioning

confidence: 99%

Diamond—the ultimate material for exploring physics of spin-defects for quantum technologies and diamondtronics

Das¹,

Raj²,

Jana³

et al. 2022

J. Phys. D: Appl. Phys.

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Diamond due to its outstanding optical, electrical, mechanical and thermal properties finds an important place in electronic, opto-electronic and quantum technologies. Recent progresses showing superconductivity in diamond by boron doping has opened up many avenues including its applications in SQUID devices especially with polycrystalline diamond films. Granular boron doped diamond films find applications in quantum inductance devices where high surface inductance is required. Particularly important are the defect centers in diamond like nitrogen-vacancy (N-V), silicon vacancy (SiV) and other color centres which are ideal candidates for next generation quantum hardware systems. For efficient device applications, an indispensable need remains for a substitutional donor in diamond lattice that yields a lower thermal activation energy at room temperature. In this review, a comprehensive summary of research and the technological challenges has been reported including some of our latest results on nitrogen doping in polycrystalline diamond to understand the transport phenomenon emphasizing on its possible future applications.

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Strongly correlated impurity band superconductivity in diamond: X-ray spectroscopic evidence

Cited by 24 publications

References 21 publications

Superconducting group-IV semiconductors

Superconducting group-IV semiconductors

Flux pinning and improved critical current density in superconducting boron doped diamond films

Diamond—the ultimate material for exploring physics of spin-defects for quantum technologies and diamondtronics

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