Absence of electron-phonon coupling superconductivity in the bilayer phase of La3Ni2O7 under pressure

• Published in: npj quantum materials Vol. 9; no. 1; pp. 80 - 6
• Main Authors: Ouyang, Zhenfeng, Gao, Miao, Lu, Zhong-Yi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15-10-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/119/1003; 639/766/119/995; Bilayers; Charge density waves; Condensed Matter Physics; Density functional theory; Fermi surfaces; First principles; Phonons; Physics; Physics and Astronomy; Quantum Physics; Structural Materials; Superconductivity; Surfaces and Interfaces; Thin Films; Transition temperature; Unconventional superconductors
• ISSN: 2397-4648; 2397-4648
• DOI: 10.1038/s41535-024-00689-5

An experimental study found superconductivity in bilayer phase of La
3
Ni
2
O
7
, with the highest superconducting transition temperature (
T
c
) ∼ 80 K under pressure. Recently, some reports claimed that there exists a competitive monolayer-trilayer structural phase in La
3
Ni
2
O
7
compounds. We perform the first-principles calculations and find that bilayer phase of La
3
Ni
2
O
7
is energetically favorable under pressure. Although extensive studies have been done to investigate the electronic correlation and potential superconducting pairing mechanism in bilayer phase of La
3
Ni
2
O
7
, the phonon properties and electron-phonon coupling (EPC) in the high-pressure
I4/mmm
phase of La
3
Ni
2
O
7
are not reported. Using the density functional theory (DFT) combined with Wannier interpolation technique, we study the phonon properties and EPC in bilayer phase of La
3
Ni
2
O
7
under 29.5 GPa. Our findings reveal that EPC is insufficient to explain the observed superconducting
T
c
∼ 80 K. And the calculated Fermi surface nesting may explain the experimentally observed charge density wave (CDW) transition in bilayer phase of La
3
Ni
2
O
7
. Our calculations substantiate that bilayer phase of La
3
Ni
2
O
7
is an unconventional superconductor.