Predicted superconductivity in one-dimensional A₃Hf₂B₃-type electrides.

Area of Science:

• Solid State Physics and Materials Science
• Superconductivity
• Computational Materials Design

Background:

• Inorganic electrides, characterized by anionic electrons, are candidates for superconductivity.
• Most known electrides require high pressures to achieve significant superconducting transition temperatures (Tc).
• Discovering electrides that superconduct under low or moderate pressures is a key research objective.

Purpose of the Study:

• To computationally screen and identify novel superconducting electrides within the A3Hf2B3 material class.
• To investigate the electronic structures and phonon properties of potential electride candidates.
• To predict superconducting transition temperatures (Tc) for promising materials.

Main Methods:

• Density functional theory (DFT) calculations were employed to construct and analyze a series of A3Hf2B3 compounds (A = Mg, Ca, Sr, Ba; B = Si, Ge, Sn, Pb).
• Analysis included electronic structure calculations and phonon dispersion spectrums to identify stable one-dimensional electrides.
• Electron-phonon coupling calculations were performed to predict superconductivity and transition temperatures.

Main Results:

• Stable one-dimensional electrides Ca3Hf2Ge3, Ca3Hf2Sn3, and Sr3Hf2Pb3 were identified.
• Superconductivity was predicted for these electrides, with Sr3Hf2Pb3 exhibiting the highest Tc of 4.02 K.
• Ca3Hf2Ge3 and Ca3Hf2Sn3 showed predicted Tcs of 1.16 K and 1.04 K, respectively. Applying 20 GPa pressure increased Ca3Hf2Ge3's Tc to 1.96 K due to phonon softening.

Conclusions:

• This study expands the library of known superconducting electrides.
• The identified materials, particularly Sr3Hf2Pb3, are promising candidates for low-pressure superconductivity research.
• The findings provide significant guidance for the design and synthesis of novel electride and superconducting materials.