Abstract Experiments investigating magnetic-field-tuned superconductor–insulator transition (HSIT) mostly focus on two-dimensional material systems where the transition and its proximate ground-state phases, often exhibit features that are seemingly at odds with the expected behavior. Here we present a complementary study of a three-dimensional pressure-packed amorphous indium-oxide (InOx) powder where granularity controls the HSIT. Above a low threshold pressure of ∼0.2 GPa, vestiges of superconductivity are detected, although neither a true superconducting transition nor insulating behavior are observed. Instead, a saturation at very high resistivity at low pressure is followed by saturation at very low resistivity at higher pressure. We identify both as different manifestations of anomalous metallic phases dominated by superconducting fluctuations. By analogy with previous identification of the low resistance saturation as a ‘failed superconductor’, our data suggests that the very high resistance saturation is a manifestation of a ‘failed insulator’. Above a threshold pressure of ∼6 GPa, the sample becomes fully packed, and superconductivity is robust, withTCtunable with pressure. A quantum critical point atPC∼ 25 GPa marks the complete suppression of superconductivity. For a finite pressure belowPC, a magnetic field is shown to induce a HSIT from a true zero-resistance superconducting state to a weakly insulating behavior. Determining the critical field,HC, we show that similar to the 2D behavior, the insulating-like state maintains a superconducting character, which is quenched at higher field, above which the magnetoresistance decreases to its fermionic normal state value.
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Anomalous behavior in high-pressure carbonaceous sulfur hydride
A new experimental study by Snider et al. [Nature 586, 373-377 (2020)] reported behavior in a high-pressure carbon-sulfur-hydrogen system that has been interpreted by the authors as superconductivity at room temperature. The sudden drop of electrical resistance at a critical temperature and the change of the R vs. T behavior with an applied magnetic field point to superconductivity. This is a very exciting study in one of the most important areas of science, hence, it is crucial for the community to investigate these findings and hopefully reproduce these results. In this comment, we present calculations that expand upon the arguments put forth by Hirsch and Marsiglio [arXiv:2010.10307], and offer some speculations about physical mechanisms that might explain the observed data. In agreement with Hirsch and Marsiglio, we show that there are errors in the analysis presented in the experimental paper, and with the correct analysis, the reported R vs. T data significantly deviate from the expected behavior. In particular, the extremely sharp change in resistance at the superconducting transition is not consistent with a strongly type II superconductor.
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- Award ID(s):
- 1926004
- PAR ID:
- 10289600
- Date Published:
- Journal Name:
- Physical chemistry chemical physics
- ISSN:
- 1463-9076
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Maps showing the estimated territorial boundaries of all bird species occupying the 10-ha bird plot in the Hubbard Brook Experimental Forest, 1969-2021. These data were used in estimating the abundance of bird populations during this period (e.g., Holmes and Sturges 1975, Holmes et al. 1986, Holmes and Sherry 1988, 2001, Holmes 2011). These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. Papers associated with this dataset: Holmes, R. T., & Sturges, F. W. (1975). Bird Community Dynamics and Energetics in a Northern Hardwoods Ecosystem. Journal of Animal Ecology, 44(1), 175–200. https://doi.org/10.2307/3857 Sherry, T. W. (1979). Competitive interactions and adaptive strategies of American Redstarts and Least Flycatchers in a northern hardwoods forest. The Auk, 96(2), 265-283. Holmes, R. T., Bonney, R. E., & Pacala, S. W. (1979). Guild Structure of the Hubbard Brook Bird Community: A Multivariate Approach. Ecology, 60(3), 512–520. https://doi.org/10.2307/1936071 Holmes, R. T., Sherry, T. W., & Sturges, F. W. (1986). Bird Community Dynamics in a Temperate Deciduous Forest: Long-Term Trends at Hubbard Brook. Ecological Monographs, 56(3), 201–220. https://doi.org/10.2307/2937074 Holmes, R. T., & Robinson, S. K. (1988). Spatial patterns, foraging tactics, and diets of ground-foraging birds in a northern hardwoods forest. The Wilson Bulletin, 377-394. Holmes, R. T., & Sherry, T. W. (1988). Assessing population trends of New Hampshire forest birds: local vs. regional patterns. The Auk, 105(4), 756-768. 10.2307/4087390 Holmes, R. T., & Sherry, T. W. (2001). Thirty-year bird population trends in an unfragmented temperate deciduous forest: importance of habitat change. The Auk, 118(3), 589-609. https://doi.org/10.1093/auk/118.3.589 Holmes, R. T. (2011). Avian population and community processes in forest ecosystems: Long-term research in the Hubbard Brook Experimental Forest. Forest Ecology and Management, 262(1), 20-32. https://doi.org/10.1016/j.foreco.2010.06.021 Associated datasets in the data catalog: Holmes, R.T., N.L. Rodenhouse, and M.T. Hallworth. 2022. Bird Abundances at the Hubbard Brook Experimental Forest (1969-present) and on three replicate plots (1986-2000) in the White Mountain National Forest ver 8. Environmental Data Initiative. https://doi.org/10.6073/pasta/6422a72893616ce9020086de5a5714cd (Accessed 2023-12-17).more » « less
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