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# Direct spectroscopic evidence for phase competition between the pseudogap and superconductivity in Bi2Sr2CaCu2O8+δ

## Abstract

In the high-temperature (Tc) cuprate superconductors, a growing body of evidence suggests that the pseudogap phase1, existing below the pseudogap temperature T, is characterized by some broken electronic symmetries distinct from those associated with superconductivity2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21. In particular, recent scattering experiments have suggested that charge ordering competes with superconductivity18,19,20,21. However, no direct link of an interplay between the two phases has been identified from the important low-energy excitations. Here, we report an antagonistic singularity at Tc in the spectral weight of Bi2Sr2CaCu2O8+δ as compelling evidence for phase competition, which persists up to a high hole concentration p ~ 0.22. Comparison with theoretical calculations confirms that the singularity is a signature of competition between the order parameters for the pseudogap and superconductivity. The observation of the spectroscopic singularity at finite temperatures over a wide doping range provides new insights into the nature of the competitive interplay between the two orders and the complex phase diagram near the pseudogap critical point.

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## Acknowledgements

We thank S. Kivelson, H. Yao, A. Millis, D. Scalapino, P. Hirshfeld, B. Markiewicz, D-H. Lee, L. Yu, A. Fujimori and N. Nagaosa for fruitful discussions. ARPES experiments were performed at the Stanford Synchrotron Radiation Lightsource, operated by the Office of Basic Energy Science, US DOE. This work is supported by DOE Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract DE-AC02-76SF00515.

## Author information

Authors

### Contributions

M.H., T.P.D. and Z-X.S. conceived the experiment. M.H., R-H.H., I.M.V., Y.H. and K.T. carried out ARPES measurements with the assistance of D.L. and R.G.M. M.H. analysed the data. Y.Y., M.I., T.S., K.F. and S.I. synthesized and characterized bulk single crystals. E.A.N., B.M. and T.P.D. performed theoretical calculations. All authors contributed to the scientific planning and discussions.

### Corresponding authors

Correspondence to Makoto Hashimoto or Zhi-Xun Shen.

## Ethics declarations

### Competing interests

The authors declare no competing financial interests.

## Supplementary information

### Supplementary Information

Supplementary Information (PDF 2294 kb)

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Hashimoto, M., Nowadnick, E., He, RH. et al. Direct spectroscopic evidence for phase competition between the pseudogap and superconductivity in Bi2Sr2CaCu2O8+δ. Nature Mater 14, 37–42 (2015). https://doi.org/10.1038/nmat4116

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• DOI: https://doi.org/10.1038/nmat4116

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