Spectral density and metal-insulator phase transition in Mott insulators within reduced density matrix functional...

Area of Science:

• Condensed matter physics
• Quantum chemistry
• Materials science

Background:

• Calculating electronic structure and spectra of solids is crucial for understanding material properties.
• Reduced density matrix functional theory (RDMFT) offers a computationally efficient alternative to traditional many-body methods.
• Phase transitions in materials like Manganese Oxide (MnO) require accurate theoretical descriptions.

Purpose of the Study:

• To introduce and validate a novel RDMFT-based method for computing the spectrum of periodic solids.
• To investigate the physical mechanisms behind pressure-induced phase transitions in materials.
• To elucidate the charge dynamics governing the insulator-metal transition in MnO.

Main Methods:

• Implementation of a new spectral calculation method within RDMFT for periodic systems.
• Validation against established many-body techniques through comparison of angular momentum projected spectral densities.
• Analysis of the electronic structure changes under pressure to identify phase transition drivers.

Main Results:

• The RDMFT method shows excellent agreement with established many-body techniques for spectral calculations.
• The study identifies increased crystal field splitting as the primary cause of the insulator-metal transition in MnO under pressure.
• Charge redistribution between Mn e(g) and t(2)g states is confirmed as the key mechanism.

Conclusions:

• The presented RDMFT method is a reliable tool for calculating the spectra of periodic solids.
• Understanding pressure-induced phase transitions can be achieved through detailed electronic structure analysis.
• The findings provide insights into the electronic behavior of transition metal oxides under pressure.