Novel structures and superconductivity of silane under pressure
Miguel Martinez-Canales1, Artem R Oganov, Yanming Ma
1Materia Kondentsatuaren Fisika Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, 644 Postakutxatila, 48080 Bilbo, Basque Country, Spain.
Physical Review Letters
|March 5, 2009
Summary
Researchers explored high-pressure silane (SiH4) superconductivity. Novel structures were predicted, with a layered Pbcn structure becoming superconducting at 220 GPa, exhibiting a critical temperature (Tc) of 16 K.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Computational Chemistry
Background:
- Hydrogen-rich compounds are candidates for high-temperature superconductivity.
- Recent experiments indicate silane (SiH4) superconductivity under high pressure.
Purpose of the Study:
- To characterize the crystal structure of compressed silane.
- To predict novel stable structures of silane at high pressures.
- To investigate the pressure-induced metallization and superconductivity in silane.
Main Methods:
- Ab initio evolutionary algorithm for crystal structure prediction.
- Density Functional Theory (DFT) calculations.
- Phonon spectrum analysis.
Main Results:
- Two new silane structures (Fdd2 and Pbcn) predicted stable at 25-55 GPa and 220-250 GPa, respectively.
- Silane predicted to become metallic and superconducting in the Pbcn phase at 220 GPa.
- Theoretical critical temperature (Tc) for superconductivity calculated to be 16 K.
- Imaginary phonons in a proposed P63 structure identified as precursors to the Pbcn structure.
Conclusions:
- The Pbcn structure is identified as a stable, superconducting phase of silane at high pressures.
- Computational predictions provide a pathway for experimental verification of silane superconductivity.
- Understanding pressure-induced structural transitions is key to discovering novel superconducting materials.
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