A beginner's guide to the modern theory of polarization

TL;DR

This paper introduces the modern theory of polarization, explaining how it rigorously defines spontaneous polarization in solids and enables its calculation using Berry phase in electronic structure methods.

Contribution

It provides a simple qualitative overview of the modern theory of polarization and its computational approach via Berry phase.

Findings

Defines spontaneous polarization rigorously

Explains Berry phase computation method

Simplifies understanding of polarization in solids

Abstract

The so-called {\it Modern Theory of Polarization}, which rigorously defines the spontaneous polarization of a period solid and provides a route for its computation in electronic structure codes through the Berry phase, is introduced in a simple qualitative discussion.