Superconducting Dome in La_{3-x}Sr_{x}Ni_{2}O_{7-δ} Thin Films

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• Ambient-pressure superconductivity in La_{3}Ni_{2}O_{7} thin films offers a unique platform for studying high-temperature superconductivity.
• Compressive epitaxial strain is a key factor in achieving superconductivity in these materials.

Purpose of the Study:

• To systematically map the phase diagram of compressively strained La_{3-x}Sr_{x}Ni_{2}O_{7-δ} thin films.
• To investigate the relationship between doping, oxygen content, and superconducting properties.
• To understand the underlying mechanisms of unconventional superconductivity in nickelates.

Main Methods:

• Thin film deposition and characterization.
• Systematic tuning of Strontium (Sr) doping and oxygen content.
• Measurement of superconducting transition temperature (T_{c}) and Hall coefficient (R_{H}).
• Analysis of resistivity and insulating/metallic regimes.

Main Results:

• A superconducting dome was revealed in the phase diagram with an electron-hole crossover.
• The maximum T_{c} correlated with an anomalous sign change in R_{H}, suggesting Fermi surface reconstruction.
• ln(1/T) insulating and T-linear resistivity regimes were observed, similar to cuprates and infinite-layer nickelates.

Conclusions:

• A dome-shaped relationship between T_{c} and R_{H} was established.
• The study provides a framework for understanding unconventional superconductivity in nickelate systems.
• Compressive strain in La_{3}Ni_{2}O_{7} thin films is crucial for exploring novel superconducting phenomena.