Hidden singularities in spontaneously polarized molecular solids.

Area of Science:

• Materials Science
• Physical Chemistry
• Astrochemistry

Background:

• Spontaneous polarization in dipolar molecule films is crucial for molecular optoelectronics and understanding interstellar ice properties.
• Polarization is expected to decrease with increasing deposition temperature due to dipole orientation.

Purpose of the Study:

• To investigate the non-intuitive temperature dependence of polarization in molecular films.
• To develop a theoretical model explaining observed polarization anomalies.

Main Methods:

• Experimental observation of polarization in cis-methyl formate, 1-propanol, and ammonia films.
• Development of a continuous analytic model for polarization as a function of deposition temperature (T).

Main Results:

• Observed minima and maxima in polarization versus temperature for specific molecular films.
• Developed an analytic form for polarization vs. T that is non-differentiable, with singularities at extrema.
• This behavior is unique to dipolar films and not seen in spin glasses.

Conclusions:

• The study reveals exotic, non-monotonic temperature-dependent polarization in molecular films.
• A novel analytic model captures these singularities, offering insights into molecular ordering.
• Findings have implications for molecular devices and astrochemistry.