Mode-Selective Coupling of Coherent Phonons to the Bi2212 Electronic Band Structure

S-L Yang; J A Sobota; Y He; D Leuenberger; H Soifer; H Eisaki; P S Kirchmann; Z-X Shen

doi:10.1103/PhysRevLett.122.176403

Mode-Selective Coupling of Coherent Phonons to the Bi2212 Electronic Band Structure

Phys Rev Lett. 2019 May 3;122(17):176403. doi: 10.1103/PhysRevLett.122.176403.

Authors

S-L Yang^{1

2}, J A Sobota^{1

3}, Y He^{1

2}, D Leuenberger^{1

2}, H Soifer¹, H Eisaki⁴, P S Kirchmann¹, Z-X Shen^{1

2}

Affiliations

¹ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
² Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
³ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
⁴ Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8558, Japan.

PMID: 31107058
DOI: 10.1103/PhysRevLett.122.176403

Abstract

Cuprate superconductors host a multitude of low-energy optical phonons. Using time- and angle-resolved photoemission spectroscopy, we study coherent phonons in Bi_{2}Sr_{2}Ca_{0.92}Y_{0.08}Cu_{2}O_{8+δ}. Sub-meV modulations of the electronic band structure are observed at frequencies of 3.94±0.01 and 5.59±0.06 THz. For the dominant mode at 3.94 THz, the amplitude of the band energy oscillation weakly increases as a function of momentum away from the node. Theoretical calculations allow identifying the observed modes as CuO_{2}-derived A_{1g} phonons. The Bi- and Sr-derived A_{1g} modes which dominate Raman spectra in the relevant frequency range are absent in our measurements. This highlights the mode selectivity for phonons coupled to the near-Fermi-level electrons, which originate from CuO_{2} planes and dictate thermodynamic properties.