Record high T_c element superconductivity achieved in titanium

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Conventional BCS theory typically does not favor superconductivity in transition metals due to d-electron behavior.
• Discovering high-temperature superconductivity (SC) in elemental materials remains a significant challenge.

Purpose of the Study:

• To experimentally investigate superconductivity in titanium under extreme pressure conditions.
• To explore unconventional mechanisms driving high-temperature superconductivity in simple materials.

Main Methods:

• High-pressure experiments were conducted on titanium.
• Superconducting transition temperatures (Tc) were measured across a wide pressure range.
• Critical magnetic fields (Hc2) and coherence lengths were estimated.

Main Results:

• Superconductivity was observed in titanium at pressures from 108 GPa to 310 GPa.
• Record high Tc values were achieved, with Tc onset above 26.2 K and zero resistance Tc of 21 K.
• Estimated Hc2(0) reached approximately 32 Tesla with a coherence length of 32 Å.
• Evidence suggests strong s-d electron transfer and d-band dominance, indicating correlation-driven SC.

Conclusions:

• The discovery of high Tc superconductivity in titanium under pressure challenges existing theoretical models based solely on electron-phonon coupling.
• The findings highlight the potential of pressure-tuned unconventional mechanisms for discovering high-Tc superconductors in simple elemental systems.
• This research opens a new pathway for the rational design and discovery of novel superconducting materials.