Thermo-electric transport in Van der Waal junctions.
When two planar atomic membranes are placed within the van der Waals distance, the charge and heat transport across the interface are coupled by the rules of momentum conservation and structural commensurability, lead to outstanding thermoelectric properties. My research focuses on exploring the electric and thermoelectric transport across the van der Waals gap formed in twisted bilayer graphene (tBLG). The Tunability of cross-plane Seebeck effect in van der Waals junctions may be valuable in creating a new genre of versatile thermoelectric systems with layered solids.
Publications: “Seebeck coefficient of a single van der Waals junction in twisted bilayer graphene”, P. S. Mahapatra, K. Sarkar, H. R. Krishnamurthy, S. Mukerjee and A. Ghosh(accepted Nano Letters DOI:10.1021/acs.nanolett.7b03097)
Electronic and Structural properties of Interface engineered atomically thin 2-D crystals:
Transition Metal Di-Chalcogenides (TMDCs) have gained enormous attention due to their rich electronic and structural properties i.e. direct Eg in 1L, thickness dependent Eg, spin valley coupling etc. Although TMDCs are normally semiconductors, It has been theoretically predicted that they can have a variety of crystalline phases which are normally unstable. A novel technique to stabilize one such ferroelectric phase in MoS2 has been discovered. Our spectroscopic and electronic evidences confirm that 1L MoS2 can be converted into a ferroelectric. The ferroelectric negative capacitance is being subsequently used to break the theoretical lower limit of subthreshold slope in FET.
Electronic, optoelectronic and low frequency noise measurements in transition metal dichalcogenide (TMDC) field effect transistors. Fabrication and characterization of TMDC based heterostructures aimed at optical and ferroelectric applications.
My research focuses on probing magnetism along grain boundaries in 2D materials. Grain boundaries have long been considered a bane in the large scale fabrication of 2D materials such as graphene and transition metal dichalcogenides (TMDCs) by chemical vapour deposition (CVD) leading to polycrystallinity and poor structural and electrical performance. However, recent theoretical studies have predicted the manifestation of magnetism along such grain boundaries due to the nature of defects that constitute them. It will be interesting to probe and quantify the magnetic field strength arising out of these structural defects and suggest potential applications for their use in spintronics, spin filters or even in the hunt for the elusiveMajorana fermions.