Enhanced superconductivity in metallic oxides near the metal-insulator transition

Osofsky, M. S.; Soulen, R. J.; Claassen, J. H.; Trotter, Geoff; Kim, Heung Soo; Horwitz, J. S.

doi:10.1103/physrevb.66.020502

Cited by 13 publications

(7 citation statements)

References 35 publications

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“…Rescaling the coupling and screening parameters and µ* according to power laws close to the critical concentration has been proposed for diamond 40 and silicon 41 but remains specific and unsatisfactory. More general descriptions 42,43 of the effect of approaching the MIT in disordered metals yield TC enhancements which have not been detected in the materials under study here. Unfortunately, the powerful parameter-free approach where the Coulomb pseudo-potential µ does not need to be adjusted 44 has not been applied to any of the superconducting semiconductors so far.…”

mentioning

confidence: 55%

Superconductivity in doped semiconductors

Bustarret

2015

Physica C: Superconductivity and its Applications

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International audienceA historical survey of the main normal and superconducting state properties of several semiconductors doped into superconductivity is proposed. This class of materials includes selenides, tellurides, oxides and column-IV semiconductors. Most of the experimental data point to a weak coupling pairing mechanism, probably phonon-mediated in the case of diamond, but probably not in the case of strontium titanate, these being the most intensively studied materials over the last decade. Despite promising theoretical predictions based on a conventional mechanism, the occurrence of critical temperatures significantly higher than 10 K has not been yet verified. However, the class provides an enticing playground for testing theories and devices alike

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mentioning

confidence: 55%

Superconductivity in doped semiconductors

Bustarret

2015

Physica C: Superconductivity and its Applications

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“…These localised islands of superconductivity proliferate as the temperature is lowered, resulting in a spatially distributed collection of domains with varying superconducting T c . The effect could also be indicative of that seen in disordered metals close to the MIT 25,26 .…”

Section: Experimental Methodsmentioning

confidence: 72%

Irradiation-Induced Modification of the Superconducting Properties of Heavily-Boron-Doped Diamond

Creedon

Ganesan

et al. 2018

Phys. Rev. Applied

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Diamond, a wide band-gap semiconductor, can be engineered to exhibit superconductivity when doped heavily with boron. The phenomena has been demonstrated in samples grown by chemical vapour deposition where the boron concentration exceeds the critical concentration for the metal-to-insulator transition of nMIT 4 × 10 20 /cm 3 . While the threshold carrier concentration for superconductivity is generally well established in the literature, it is unclear how well correlated higher critical temperatures are with increased boron concentration. Previous studies have generally compared several samples grown under different plasma conditions, or on substrates having different crystallographic orientations, in order to vary the incorporation of boron into the lattice. Here, we present a study of a single sample with unchanging boron concentration, and instead modify the charge carrier concentration by introducing compensating defects via high energy ion irradiation. Superconductivity is completely suppressed when the number of defects is sufficient to compensate the hole concentration to below threshold. Furthermore, we show it is possible to recover the superconductivity by annealing the sample in vacuum to remove the compensating defects. arXiv:1809.01800v1 [cond-mat.supr-con]

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“…Such a view, where both l and m Ã are rescaled by the proximity of the metal-to-insulator transition (MIT), is not so common although the influence of the proximity of the MIT on the superconducting behaviour of disordered metals has been studied extensively in order to explain the enhancement of T c in the vicinity of the MIT (Osofsky et al 2001(Osofsky et al , 2002Soulen et al 2003). Such an enhancement has not been reported for diamond so far.…”

Section: Doping-induced Normal-to-superconducting Transitionmentioning

confidence: 96%

“…Under the assumption that equation (4.1) still applied despite the fact that close to n c the Fermi energy becomes smaller than the phonon energy, those relatively high values of T c could be explained (Klein et al 2007) by a slow variation of the electron-phonon coupling parameter, l (typically lw(n B /n c K1) 0.2 ), together with a pronounced but gradual decrease in the screening parameter m Ã when n B /n c . Such a view, where both l and m Ã are rescaled by the proximity of the metal-to-insulator transition (MIT), is not so common although the influence of the proximity of the MIT on the superconducting behaviour of disordered metals has been studied extensively in order to explain the enhancement of T c in the vicinity of the MIT (Osofsky et al 2001(Osofsky et al , 2002Soulen et al 2003). Such an enhancement has not been reported for diamond so far.…”

Section: Doping-induced Normal-to-superconducting Transitionmentioning

confidence: 99%

Metal-to-insulator transition and superconductivity in boron-doped diamond

Bustarret

Achatz

Sacépé

et al. 2007

Phil. Trans. R. Soc. A.

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The experimental discovery of superconductivity in boron-doped diamond came as a major surprise to both the diamond and the superconducting materials communities. The main experimental results obtained since then on single-crystal diamond epilayers are reviewed and applied to calculations, and some open questions are identified. The critical doping of the metal-to-insulator transition (MIT) was found to coincide with that necessary for superconductivity to occur. Some of the critical exponents of the MIT were determined and superconducting diamond was found to follow a conventional type II behaviour in the dirty limit, with relatively high critical temperature values quite close to the doping-induced insulator-to-metal transition. This could indicate that on the metallic side both the electron-phonon coupling and the screening parameter depend on the boron concentration. In our view, doped diamond is a potential model system for the study of electronic phase transitions and a stimulating example for other semiconductors such as germanium and silicon.

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Enhanced superconductivity in metallic oxides near the metal-insulator transition

Cited by 13 publications

References 35 publications

Superconductivity in doped semiconductors

Superconductivity in doped semiconductors

Irradiation-Induced Modification of the Superconducting Properties of Heavily-Boron-Doped Diamond

Metal-to-insulator transition and superconductivity in boron-doped diamond

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