Speaker and Affliation:
Prof. Umesh V. Waghmare
Theoretical Sciences Unit
Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR)
Bengaluru 560064, India
24th December, 2020 (Thursday), 04:00 PM (India Standard Time)
Introducing fundamental aspects of ferroelectricity in bulk oxide crystals, we highlight how its sensitivity to surrounding makes its evolution to nano-scale films of materials quite interesting and relevant to miniaturization of devices. Using first-principles theoretical analysis, we predict ferroelectricity in 2-D materials like 1T-MoS2 and h-NbN, and demonstrate how it originates from strongly coupled electrons and phonons. While these allow dipolectronic devices based on ultimately thin active channels, experimental realization of such devices and their scalable fabrication are quite challenging. To this end, we report scale-free ferroelectricity in which sub-nano meter thin ferroelectric layers are naturally embedded in 2-dimensional crystalline architecture of orthorhombic structure of HfO2, a material that is already a part of current semiconductor technologies, opening up ultimately high density ferroelectric memory devices.
Work done in collaboration with Anuja Chanana, S Anand, K Mohan, Anjali Singh and Sharmila N Shirodkar and Jun Hee Lee group.