Signatures of ambient pressure superconductivity in thin film La3Ni2O7

Eun Kyo Ko; Yijun Yu; Yidi Liu; Lopa Bhatt; Jiarui Li; Vivek Thampy; Cheng-Tai Kuo; Bai Yang Wang; Yonghun Lee; Kyuho Lee; Jun-Sik Lee; Berit H Goodge; David A Muller; Harold Y Hwang

doi:10.1038/s41586-024-08525-3

Signatures of ambient pressure superconductivity in thin film La₃Ni₂O₇

Nature. 2024 Dec 19. doi: 10.1038/s41586-024-08525-3. Online ahead of print.

Authors

Eun Kyo Ko^#^{1

2}, Yijun Yu^#^{3

4}, Yidi Liu^{5

6}, Lopa Bhatt⁷, Jiarui Li^{5

8}, Vivek Thampy⁹, Cheng-Tai Kuo⁹, Bai Yang Wang^{5

6}, Yonghun Lee^{5

8}, Kyuho Lee^{5

6}, Jun-Sik Lee⁹, Berit H Goodge¹⁰, David A Muller^{7

11}, Harold Y Hwang^{12

13}

Affiliations

¹ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA. [email protected].
² Department of Applied Physics, Stanford University, Stanford, CA, USA. [email protected].
³ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA. [email protected].
⁴ Department of Applied Physics, Stanford University, Stanford, CA, USA. [email protected].
⁵ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
⁶ Department of Physics, Stanford University, Stanford, CA, USA.
⁷ School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
⁸ Department of Applied Physics, Stanford University, Stanford, CA, USA.
⁹ Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
¹⁰ Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.
¹¹ Kavli Institute at Cornell for Nanoscale Technology, Cornell University, Ithaca, NY, USA.
¹² Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA. [email protected].
¹³ Department of Applied Physics, Stanford University, Stanford, CA, USA. [email protected].

^# Contributed equally.

PMID: 39701131
DOI: 10.1038/s41586-024-08525-3

Abstract

Recently, the bilayer nickelate La₃Ni₂O₇ has been discovered as a new superconductor with transition temperature T_c near 80 K under high pressure^1-3. Despite extensive theoretical and experimental work to understand the nature of its superconductivity^4-29, the requirement of extreme pressure restricts the use of many experimental probes and limits its application potential. Here, we present signatures of superconductivity in La₃Ni₂O₇ thin films at ambient pressure, facilitated by the application of epitaxial compressive strain. The onset T_c varies approximately from 26 K to 42 K, with higher T_c values correlating with smaller in-plane lattice constants. We observed the co-existence of other Ruddlesden-Popper phases within the films and dependence of transport behavior with ozone annealing, suggesting that the observed low zero resistance T_c of around 2 K can be attributed to stacking defects, grain boundaries, and oxygen stoichiometry. This finding initiates numerous opportunities to stabilize and study superconductivity in bilayer nickelates at ambient pressure, and to facilitate the broad understanding of the ever-growing number of high temperature and unconventional superconductors in the transition metal oxides.