Unconventional spectral signature of Tc in a pure d-wave superconductor

Su-Di Chen; Makoto Hashimoto; Yu He; Dongjoon Song; Jun-Feng He; Ying-Fei Li; Shigeyuki Ishida; Hiroshi Eisaki; Jan Zaanen; Thomas P Devereaux; Dung-Hai Lee; Dong-Hui Lu; Zhi-Xun Shen

doi:10.1038/s41586-021-04251-2

Unconventional spectral signature of T_c in a pure d-wave superconductor

Nature. 2022 Jan;601(7894):562-567. doi: 10.1038/s41586-021-04251-2. Epub 2022 Jan 26.

Authors

Su-Di Chen^#^{1

2

3

4}, Makoto Hashimoto^#⁵, Yu He^{1

2

3

6}, Dongjoon Song^{7

8}, Jun-Feng He^{1

2

3

9}, Ying-Fei Li^{1

2

3}, Shigeyuki Ishida⁷, Hiroshi Eisaki⁷, Jan Zaanen¹⁰, Thomas P Devereaux^{3

11}, Dung-Hai Lee^{12

13}, Dong-Hui Lu⁵, Zhi-Xun Shen^{14

15

16}

Affiliations

¹ Department of Applied Physics, Stanford University, Stanford, CA, USA.
² Department of Physics, Stanford University, Stanford, CA, USA.
³ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA.
⁴ Kavli Energy NanoScience Institute, University of California, Berkeley, Berkeley, CA, USA.
⁵ Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
⁶ Department of Applied Physics, Yale University, New Haven, CT, USA.
⁷ National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
⁸ Center for Correlated Electron Systems, Institute for Basic Science, Seoul, Republic of Korea.
⁹ Department of Physics, University of Science and Technology of China, Hefei, China.
¹⁰ Institute Lorentz for Theoretical Physics, Leiden University, Leiden, The Netherlands.
¹¹ Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
¹² Department of Physics, University of California, Berkeley, Berkeley, CA, USA.
¹³ Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
¹⁴ Department of Applied Physics, Stanford University, Stanford, CA, USA. zxshen@stanford.edu.
¹⁵ Department of Physics, Stanford University, Stanford, CA, USA. zxshen@stanford.edu.
¹⁶ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA, USA. zxshen@stanford.edu.

^# Contributed equally.

PMID: 35082417
DOI: 10.1038/s41586-021-04251-2

Abstract

In conventional superconductors, the phase transition into a zero-resistance and perfectly diamagnetic state is accompanied by a jump in the specific heat and the opening of a spectral gap¹. In the high-transition-temperature (high-T_c) cuprates, although the transport, magnetic and thermodynamic signatures of T_c have been known since the 1980s², the spectroscopic singularity associated with the transition remains unknown. Here we resolve this long-standing puzzle with a high-precision angle-resolved photoemission spectroscopy (ARPES) study on overdoped (Bi,Pb)₂Sr₂CaCu₂O_8+δ (Bi2212). We first probe the momentum-resolved electronic specific heat via spectroscopy and reproduce the specific heat peak at T_c, completing the missing link for a holistic description of superconductivity. Then, by studying the full momentum, energy and temperature evolution of the spectra, we reveal that this thermodynamic anomaly arises from the singular growth of in-gap spectral intensity across T_c. Furthermore, we observe that the temperature evolution of in-gap intensity is highly anisotropic in the momentum space, and the gap itself obeys both the d-wave functional form and particle-hole symmetry. These findings support the scenario that the superconducting transition is driven by phase fluctuations. They also serve as an anchor point for understanding the Fermi arc and pseudogap phenomena in underdoped cuprates.

Publication types

Research Support, Non-U.S. Gov't