Proton disorder in cubic ice: Effect on the electronic and optical properties

Area of Science:

• Condensed matter physics
• Materials science
• Computational chemistry

Background:

• Proton disorder in ice influences key properties like ferroelectricity and growth modes.
• While structural transitions are well-studied, electronic and optical properties under varying proton disorder remain less understood.

Purpose of the Study:

• To investigate the electronic and optical properties of cubic ice with varying degrees of proton disorder.
• To compare these properties with those of fully disordered liquid water.

Main Methods:

• Ab initio many-body perturbation theory calculations.
• Systematic variation of proton disorder levels in cubic ice.
• Comparison with liquid water as a disordered reference system.

Main Results:

• Increasing proton disorder leads to a reduction in the electronic band gap of ice.
• Excitonic binding energy decreases with increasing proton disorder.
• The calculated optical gaps show minimal dependence on the degree of proton disorder.

Conclusions:

• The interplay between local dipolar disorder and electronic correlation governs the electronic and optical properties of ice.
• Despite changes in electronic and excitonic properties, the optical gap remains remarkably stable across different proton disorder levels.