Welcome to the Functional Thin Films and Electron Microscopy Laboratory at CeNSE, IISc Bangalore. We are an experimental group, who routinely challenge the conventional wisdom of materials design for electronic, MEMS, electrooptic and neuromorphic applications. Our answer more often than not is defect-engineering. We work on a wide variety of materials systems spanning from complex oxides to simple oxides to chalcogenides.

Here is a glimpse of our research activity:

• Ferroelectric materials are generally polar (space groups) in nature. We ask the question, is a polar phase always necessary to obtain ferroelectricity? Is it possible to engineer it through a defect-based (point charged defects) pathway? In this context, based on our deep insights into ferroelectricity in fluorites (hafnia-based), we are embarking on generalizing these principles of ferroelectricity to other simple Si-friendly oxides.

• Piezoelectric materials that give large electromechanical response do not possess centrosymmetry, and are dielectrically soft materials. These are Si incompatible (PZT for e.g.). We again ask the question is it possible to design materials with large electromechanical coefficients on simpler, non-toxic Si friendly materials using smart techniques of defect engineering. In this context, we are exploring a plethora of defective oxides, and understanding the guidelines to create materials with large electrostrictive and electrooptic coefficients (doped Ceria, defective barium titanate etc).
• We are trying to understand polar topologies in various ferroelectric materials, and exploring the possible analogies between their dynamics and neural networks.
• We are looking at quantum materials such as correlated nickelates and vanadates to create neural oscillators.
• We are exploring the applicability of a dislocation assisted (solid-state) ultra-low power phase change in thin-film phase-change materials. In the past on nanowire devices, we have been able to drastically decrease the amorphization power/current densities in phase change materials via defect engineering.

For these various activities, we synthesize materials in our laboratory using state-of-the-art pulsed laser deposition and RF sputtering systems, characterize them through a plethora of structure-property measurement techniques. We make electronic devices such as ferroelectric tunnel junctions, ferroelectric capacitors,  phase change memory devices, memristors etc. ourselves but collaborate with our colleagues for MEMS and electro-optic devices and applications. We are developing a suite of in situ microscopy techniques at IISc to observe the real devices under operation.