Shankari Nadupalli, M.Sc., Ph.D.
- Pracoviště
- Katedra fyziky kondenzovaných látek
- shankari.nadupalli@matfyz.cuni.cz
- Místnost / budova
- L 264 (313), 2. patro, Těžké laboratoře Troja, V Holešovičkách 747/2, Praha 8
- L 265 (313), 2. patro, Těžké laboratoře Troja, V Holešovičkách 747/2, Praha 8
Interests and science escapades
I am interested in working with materials that exhibit coupling between magnetic (spin) – electric (polarization) – light induced (polaron/photon-induced) properties.
Until now, my work focused on light-induced phenomenon in multiferroic materials. When I investigate such phenomena, I try to understand the influence of structure-symmetry-disorder-defects on physical properties such as dielectric, piezoelectric, pyroelectric, ferroelectric, bulk-photovoltaic and piezo-photovoltaic effects. Such investigations allow me to have a complete picture of symmetry/non-centrosymmetry dependent physical coefficients which then pave a path to informed experiments. Oftentimes, I look for symmetry breaking phenomenon or physical properties that do not play by the rules. The fun is in the unknown!
I also enjoy looking at the effects of size and morphology on the electronic structure of polar oxides/ metal oxides. My collaborators and I have unveiled beautiful correlations between crystal dimension/morphology and defect localization. We showed a variety of defect-defect interactions that may alter the electronic structure of the material resulting in unique optical phenomenon. We also showed that defect interactions and particularly their localisation have a direct consequence on the optical properties of metal oxides.
I am keen in understanding more about defect/dopant induced strain and their effects on physical properties. The magnitude of strain has a dramatic difference in 2D materials when compared with thin films/ 2D materials. Strain-induced effects on thin-films and 2D materials is a topic that fascinates me now.
In 2022, I measured the phase transitions in complex solid solutions using a technique that is ignored by most material scientists – Birefringence microscopy. This technique is a simple yet a powerful method to measure anisotropy in ordered/disordered materials. One can strat from measuring chirality, change in disorder, pin-pointing phase transitions in crystals to measuring structure in fibres and polymers.
One of my works that I personally like is the one that i hope to extend beyond a published article. It is a hypothesis indicating topological phenomenon in polar oxide/perovskite crystals that exhibit magnetoelectric effects. In this case we take Bismuth Ferrite, with its canted spin cycloid as an example. In the last few years, scientific communications on skin layers and its disorder suggest a possibility to detect topological ferromagnetism in bismuth ferrite provided the thickness of the film is lower than its spin cycloid period. The hypothesis is that ultra-thin films of BFO may have uncompensated spins on the surface and compensated spin disorder in the subsequent layers. This may result in a ferromagnetic surface layer and antiferromagnetic sub-surface layers. Such hypothesis leads to two questions: Would the topological ferromagnetism be an alternative to epitaxial strain-induced amplification of magnetoelectric effect? Would the topological spin distortion due the skin layer compete with the spin-exchange phenomenon in doped BFO? Provided the disorder that makes BFO ferromagnetic extends through the sample (long-range), would that reduce the amount of voltage required to switch the spin in BFO by orders of magnitude (an attojoule switching device)? These are the avenues I would like to venture at the moment.
In summary, I like to investigate the microscopic origins of macroscopic effects in a system.
Qualifications
- PhD in Physics (University of Luxembourg)
- Post-graduate diploma in Patents Law (NALSAR University of Law, India)
- Integrated Master’s in Technology – Nanotechnology (Amity university, India)
Work experience
- Post-Doctoral researcher (Tel Aviv University, Israel)
- Internships and short projects at:
- Imec (Leuven), Belgium
- National Aerospace Laboratory, India
- Indian Institute of Chemical technology, India