Visualizing Brakhausen's noise induced solid state amorphization in 2D ferroelectrics

Solid state amorphization as against melt-quench amorphization  offers energy efficient glass transition pathways, and in context of devices such as phase change memory this translates to low power and high endurance memories. Here we show that In2Se3, a 2D ferroelectric material, responds to in-plane electric field by layer sliding, rotations and associated ferroelastic phase transitions. The defects created interact with each other generating earthquake-like  shocks which propagates disorder in longer range, and helps construct a crystal-amorphous transition pathway. This type of shock induced amorphization requires the material to be van der Waals, piezoelectric and semiconducting, and In2Se3 has all the three properties in it. I will show how operando high resolution TEM tools we developed at IISc, helped us visualize this novel mechanism of ultra-low power amorphization. 

References:

G. Modi, S. Parate, ..., P. Nukala*, R. Agarwal*, Nature, 635, 843,  2024