We are interested in materials that exhibit novel phenomena and are of technological importance. They include smart materials such as ferroelectrics, multiferroics, dilute magnetic piezoelectrics and electroactive polymers. We are exploring new functionalities of materials with nano-scale structure, such as super-lattices, clusters, nano-wires and nano-tubes. While applying state-of-the art techniques to studies of these systems, we are also engaged in developing new computational tools and programs in my group.
Ferroelectrics, which exhibit macroscopic electric dipole moment spontaneously, are useful as smart materials in micro-electro-mechanical systems (MEMS) and in non-volatile computer memories. The dipole moment of these materials couples with mechanical changes in the environment, making them useful as sensors and actuators. Most ferroelectrics used in technological applications today contain lead, which makes them toxic and hazardous to the environment. My group is involved in designing environment-friendly ferroelectrics that are lead-free and have properties comparable to those of the lead-based materials. Our efforts are directed towards tuning their properties by changing chemistry and structure (for example, superlattices).
Recently, many groups have shown that ferroelectricity is preserved in ultra-thin (a few nano metre thickness) films, contrary to the expectation that surface charge on films would kill ferroelectricity. My group is probing the possibilities of stripe (domains) formation that may stabilize ferroelectricity at the nano-scale, and their impact on properties and usefulness of these films. Our work involves use of first-principles effective Hamiltonians in molecular dynamics simulations, and is presently focusing on the dynamics of these domains as a function of temperature.
Multiferroics, which exhibit both electric and magnetic dipoles spontaneously, hold promise of much wider range of functionalities and applications, as both electric and magnetic fields can be used to drive their response. However, such materials are not very common in nature. In collaboration with experimental groups at JNC, we are engaged in understanding multiferroics and their properties. Our activities encompass related materials, the dilute magnetic piezoelectric semiconductors, which are crucial to the emerging field of spintronics.