Prof. V. Kanchana

Department of Physics, IIT Hyderabad

E-mail id: kanchana[at]iith.ac.in

 

 

 

Brief Bio-sketch:

Prof. V. Kanchana received her Ph.D from Anna university in 2004, later she joined as a guest scientist Max Planck institute for solid state research, and further moved to Royal institute of technology Stockholm and continued there up to 2007. In 2008, she has joined as a scientist in DMRL, Hyderabad. In 2009, she joined IIT Hyderabad as Assistant Professor. Prof. Kanchan's research interest include the first principles study of materials under extreme conditions, thermoelectric materials, magnetism, Fermi surface studies etc, and published more than 100 articles in prestigious journals. She is the recipient of several awards such as DAE young achiever award, young scientist awards for Andhra Pradesh, and was elected as associate fellow of Andhra Pradesh academy of science.

 

THERMOELECTRIC PROPERTIES OF TRANSITION METAL DICHALCOGENIDES

The present study report the electronic and thermoelectric properties of few interesting transition dichalcogenides which are less investigated in the field of thermoelectrics. The electronic and thermoelectric properties of OsX₂ (X: S, Se, Te) are reported, and a giant thermopower of 600 μV/K to 800 μV/K for a wide temperature range of 100 K to 500 K is observed for hole doping. The heavy valence bands stimulates the thermopower value for hole doping and light conduction bands enhances the electrical conductivity values for electron doping, enabling both 'n' and 'p' type doping favourable for TE applications at higher concentrations (10²⁰ cm^-3), which brings out device applications for OsX₂. Further, we present a highly versatile system ReS₂, which transforms from a semiconductor to a two dimensional metal under uni-axial compressive strain along 'a' direction in both bulk and monolayer. The 2D nature is realized from highly flat Fermi surfaces and anisotropic transport properties. Moreover the layer independent electronic structure properties are revisited and thermoelectric properties of ReS₂ in bulk, monolayer and bilayer forms reveal the competing thermoelectric (TE) coefficients in each form. The in-plane power-factor shows an enhancement over 'c'-axis value as a function of strain, which is almost two orders of magnitude. In addition, strain induced tunable in-plane anisotropy of almost one order has been observed in both bulk and monolayer ReS₂ (around 20%), which further opens up the possibility of TE application as nanowires. Our analysis unveils a wide range of application for ReS₂ in the field of thermoelectrics as bulk and thin films for a large temperature range. The magnitude of TE coefficients are comparable with other well established transition metal dichalocogenides.

 

References

1. P. C. Sreeparvathy, V. Kanchana, J. Phys.: Conden. Matter, 30, 295501 (2018)
2. PC Sreeparvathy, V Kanchana, P Anees, G Vaitheeswaran, Journal of Solid State Chemistry, 269, 138-144 (2019)