Sixfold enhancement of superconductivity in a tunable electronic nematic system
The electronic nematic phase—in which electronic degrees of freedom lower the crystal rotational symmetry—is commonly observed in high-temperature superconductors. However, understanding the role of nematicity and nematic fluctuations in Cooper pairing is often made more complicated by the coexisten...
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Published in | Nature physics Vol. 16; no. 3; pp. 346 - 350 |
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Main Authors | , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
2020
Nature Publishing Group Nature Publishing Group (NPG) |
Subjects | |
Online Access | Get full text |
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Summary: | The electronic nematic phase—in which electronic degrees of freedom lower the crystal rotational symmetry—is commonly observed in high-temperature superconductors. However, understanding the role of nematicity and nematic fluctuations in Cooper pairing is often made more complicated by the coexistence of other orders, particularly long-range magnetic order. Here we report the enhancement of superconductivity in a model electronic nematic system that is not magnetic, and show that the enhancement is directly born out of strong nematic fluctuations associated with a quantum phase transition. We present measurements of the resistance as a function of strain in Ba
1−
x
Sr
x
Ni
2
As
2
to show that strontium substitution promotes an electronically driven nematic order in this system. In addition, the complete suppression of that order to absolute zero temperature leads to an enhancement of the pairing strength, as evidenced by a sixfold increase in the superconducting transition temperature. The direct relation between enhanced pairing and nematic fluctuations in this model system, as well as the interplay with a unidirectional charge-density-wave order comparable to that found in the cuprates, offers a means to investigate the role of nematicity in strengthening superconductivity.
Transport measurements show that nematic fluctuations near a phase transition increase the temperature at which superconductivity occurs by a factor of nearly six. This happens in a non-magnetic nickel-based compound. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 FG02-06ER46285; SC0012336 USDOE Office of Science (SC) C.E. and J.P. conceived and designed the experiments. C.E., D.J.C., T.M., H.H. and T.D. synthesized crystals and performed basic physical characterization. C.E. performed elastoresistivity measurements. J.C., S.L. and P.A. performed and analysed low-temperature X-ray characterization of the CDW phase. P.Z. performed and analysed 250 K single-crystal X-ray diffraction. J.L. performed preliminary neutron diffraction studies. M.H.C. and R.M.F. developed the phenomenological model describing the evolution of nematicity in this system. C.E., J.P., R.M.F. and M.H.C. wrote the manuscript with contributions from all authors. Author contributions |
ISSN: | 1745-2473 1745-2481 |
DOI: | 10.1038/s41567-019-0736-9 |