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ML based exploration of bending flexoelectricity in vdW bilayers

ML based exploration of bending flexoelectricity in vdW bilayers

COTOFLEXI researchers propose an innovative methodology based on machine-learning inter-atomic potentials with incorporated long-range interactions to explore flexoelectric response due to the bending deformation under compression loading.

In the COTOFLEXI project, Dr. Brahmanandam Javvaji under the guidance of Prof. Xiaoying Zhuang explored the piezoelectric and flexoelectric properties of novel 2D materials with the aid of machine-learning inter-atomic potentials (MLIP). We have recently proposed an innovative methodology to explore the flexoelectric response from 2D bilayers using MLIP with incorporated long-range interactions, which has been published in “Advanced Energy Materials” (DOI: 10.1002/aenm.202201370).

Our previous works explain the mechanism and extracted the bending flexoelectric response and stretching piezoelectric response from a broader range of 2D monolayer materials. This work proposes the concept of handling of short and long-range interactions required to explore the 2D bilayer  materials. The short-range interaction parameters are derived by training the first-principle simulations prepared dataset in ML environment. The long-range interaction (vdW and CD) parameters determined by establishing a close match between MD computed values to the DFT predictions. The  derived potential parameters were validated first by comparing the elastic constants and piezoelectric constants with those by accurate DFT and available experimental reports. In this work, we analyze the compression-induced bending deformation and reported the 20 times enhanced flexoelectric coefficient for Janus diamane blayer material over the Janus MoSSe bilayer.

We show that electro-mechanical responses of novel bilayer materials with DFT level accuracy, transferability, accelerated computational cost and without the need of empirical data. The proposed methodology is applicable to investigate the novel 2D materials and their vdW heterostructures.