Observation of a V-Shape Superconductivity Evolution on Tungsten-Intercalated 2H-Type Niobium Diselenide

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid State Chemistry

Background:

• Van der Waals-layered materials like niobium diselenide (NbSe2) offer tunable electronic properties through intercalation.
• Transition metal intercalation in NbSe2 is typically studied in ordered structures to control electronic phases.
• Understanding the impact of intercalation on ground states is crucial for designing novel quantum materials.

Purpose of the Study:

• To investigate the structural and superconducting properties of tungsten (W)-intercalated 2H-NbSe2 crystals.
• To elucidate the relationship between W atom distribution, local magnetic moments, and superconductivity.
• To explore the influence of structural disorder on superconductivity in intercalated NbSe2.

Main Methods:

• Synthesis of W-intercalated 2H-NbSe2 crystals.
• Structural characterization to observe W atom distribution (ordered to disordered).
• Superconductivity measurements to track changes in critical temperature.
• Density Functional Theory (DFT) calculations to understand charge redistribution and magnetic moment formation.

Main Results:

• W intercalation leads to a transition from ordered to disordered W atom distribution with increasing concentration.
• Superconductivity exhibits an approximate V-shape suppression with increasing W intercalation, linked to induced local magnetic moments.
• Structural aberrations and inhibited ordering due to W aggregation at higher concentrations lead to superconductivity recovery.

Conclusions:

• The study demonstrates that W intercalation in 2H-NbSe2 induces competing effects on superconductivity: suppression via magnetism and recovery via structural disorder.
• Local magnetic moments around W intercalants are identified as the primary cause for superconductivity suppression at low concentrations.
• The findings highlight the potential for tuning electronic correlations and quantum phenomena in layered materials through controlled intercalation.