Ferroelectric response to interlayer shifting and rotations in trilayer hexagonal Boron Nitride

TL;DR

This study investigates the ferroelectric properties of trilayer hexagonal Boron Nitride with various stacking and rotation configurations, revealing enhanced polarization and complex mosaic-like polarization patterns.

Contribution

It provides a comprehensive first-principles analysis of polarization in trilayer h-BN, including effects of stacking and rotation, which was not previously explored in detail.

Findings

Polarization varies with stacking configurations.

Rotated layers increase polarization magnitude.

Mosaic-like polarization patterns emerge depending on stacking and rotation.

Abstract

From monolayers composed of different atoms, we can build structures with spontaneous vertical polarization by conveniently stacking multiple layers. We have studied, using first-principles methods and based on modern polarization theory, a system composed of three layers of hexagonal Boron-Nitride(h-BN) in all possible stackings. We obtain for each of the configurations how charge transfers between the layers and how it impacts on the polarization of the system. In addition, we studied a system of three layers, one of them rotated, and we found that not only did the magnitude of the polarization increase comparing with the bilayer but also, depending on the initial stacking and the rotated layer, we can create a variety of mosaic-like polarization arrangements, which are composed of regions with either triangular or hexagonal symmetry.