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Exploring correlation effects and volume collapse during electride dimensionality change in CaN.
Dmitry Y Novoselov1,2,3, Mary A Mazannikova1,2,3, Dmitry M Korotin1,2
1M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 18 S. Kovalevskaya St., Yekaterinburg, 620108, Russia. novoselov@imp.uran.ru.
Physical Chemistry Chemical Physics : PCCP
|November 8, 2023
Summary
Interstitial electronic states drive Ca2N's metal-to-semiconductor transition and volume collapse. Correlation effects and electron localization in the electride subsystem are key to this pressure-induced phase transformation.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Calcium nitride (Ca2N) exhibits complex pressure-induced phase transitions.
- Understanding the role of interstitial electronic states is crucial for explaining these transitions.
- Electride materials possess unique electronic properties due to delocalized electrons.
Purpose of the Study:
- To investigate the influence of interstitial electronic states on the metal-to-semiconductor transition in Ca2N.
- To elucidate the origin of the volume collapse during pressure-induced phase changes.
- To analyze the impact of electride subspace dimensionality changes on material properties.
Main Methods:
- Development of a simplified model incorporating the distortion of the interstitial quasi-atom (ISQ) environment under pressure.
- Application of Dynamical Mean Field Theory (DMFT) to solve the model.
- Analysis of correlation effects within the electride subsystem.
Main Results:
- Successfully reproduced the transition between metallic and semiconducting phases in Ca2N.
- Captured the significant volume collapse observed during the phase transition.
- Identified enhanced localization of excess electrons and emergence of antiferromagnetic pairing in interstitial states.
Conclusions:
- Correlation effects in the electride subsystem are essential for the complex phase transformation mechanism.
- Electron localization and antiferromagnetic pairing in interstitial states drive the spin-state transition and volume reduction.
- The study provides insights into the interplay between electronic structure, correlation, and structural changes under pressure.
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