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Pressure Dependence of Superconductivity in Single-Phase K3C60
Science (New York, N.Y.)
|June 28, 1991
Summary
Potassium-doped buckminsterfullerene (K(3)C(60)) superconductivity decreases significantly with pressure. This study measured superconducting transition temperatures under pressure, revealing insights into electronic properties.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Superconductivity Research
Background:
- Potassium-doped fullerene C(60) exhibits superconductivity at a transition temperature (T(c)) of 19.3 K at ambient pressure.
- Fullerenes are allotropes of carbon with a spherical, ellipsoidal, or hollow shape, often studied for their unique electronic properties.
Purpose of the Study:
- To investigate the effect of applied pressure on the superconducting transition temperature (T(c)) of the K(3)C(60) compound.
- To understand the pressure-induced changes in the electronic structure and density of states at the Fermi level.
Main Methods:
- Synthesis of single-phase K(3)C(60) through the reaction of alkali vapor with solid C(60) molecules.
- Measurement of magnetic susceptibility to determine bulk superconductivity.
- Application of hydrostatic pressure up to 21 kilobars using a pressure cell.
Main Results:
- A substantial decrease in the superconducting transition temperature (T(c)) of K(3)C(60) was observed with increasing pressure.
- At 21 kilobars, the T(c) dropped to below 8 K, indicating a significant pressure dependence.
- The experimental data aligns with theoretical predictions of a density of states accumulating at the Fermi level under pressure.
Conclusions:
- Pressure plays a critical role in modulating the superconducting properties of K(3)C(60).
- The observed decrease in T(c) suggests changes in the electronic band structure, specifically a piling up of states at the Fermi level.
- Further research can explore pressure-tuned superconductivity in fullerene-based materials for potential applications.
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