Publications by authors named "Supratik Mukherjee"
Article Synopsis
- A detailed study on TlTcO, a potential nuclear waste matrix, shows a phase transition from orthorhombic to tetragonal below 600 K, consistent with earlier research using X-ray diffraction.
- Observations from neutron powder diffraction revealed anomalies like large atomic displacements at low temperatures and a decrease in Tc-O bond distance with heating, suggesting changes in local structure symmetry.
- Density functional theory supports a monoclinic model for better energy efficiency, indicating that Tl's lone pairs are 'frozen' at low temperatures but become active and cause structural shifts upon heating, affecting the material's overall properties.
The present work provides insight into the structural, vibrational, and elastic properties of scheelite-type alkali-metal perrhenates AReO(= Na, K, Rb, and Cs) via first-principles calculations. Sodium, potassium, and rubidium perrhenates are isostructural and crystallize in a tetragonal structure, whereas cesium perrhenate crystallizes in an orthorhombic structure. All the phonon frequencies and their corresponding mode assignments were estimated through the linear response method within density-functional-perturbation theory.
View Article and Find Full Text PDFPair distribution function (PDF) analysis of the scheelite-type material PbWO reveals previously unidentified short-range structural distortions in the PbO polyhedra and WO tetrahedra not observed in the similarly structured CaWO. These local distortions are a result of the structural influence of the Pb 6s lone pair electrons. These are not evident from the Rietveld analysis of synchrotron X-ray or neutron powder diffraction data, nor do they strongly influence the X-ray PDF (XPDF).
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- * A study using terahertz time-domain spectroscopy (THz-TDS) measured various properties of ADNP, finding a refractive index of 1.8 and absorption coefficients ranging from 10 to 180 cm.
- * Density Functional Theory (DFT) calculations revealed six low-frequency optical phonon modes for ADNP, which showed a redshift in experimental values, suggesting anharmonicity may be influencing the results and guiding future research.
Article Synopsis
- B-N Lewis acid-base pairs are a promising but underexplored type of electronic material that could be ideal for ferroelectric applications due to their unique charge distribution and inherent dipoles.
- The study introduces an enantiomeric pair of B-N adducts called MBA-BF, which exhibit significant ferroelectric properties with measurable polarization and confirmatory piezoelectric characteristics.
- The findings highlight the potential for using MBA-BF in piezoelectric energy harvesting, achieving a notable open circuit voltage of 6.2 V, indicating their usefulness in practical applications.
Structural phase transitions drive several unconventional phenomena including some illustrious ferroic attributes which are relevant for technological advancements. On this note, we have investigated the ferroelastic structural transition of perovskite-type trigonal BaZnTeO across ∼ 150 K. With the help of Raman spectroscopy and density-functional theory (DFT)-based calculations, we report new intriguing observations associated with the phase transition in BaZnTeO.
View Article and Find Full Text PDFThis article thoroughly addresses the structural, mechanical, vibrational, electronic band structure and the optical properties of the unexplored thallous perchlorate and perbromate fromcalculations. The zone centered vibrational phonon frequencies shows, there is a blue shift in the mid and high frequency range from Cl → Br due to change in mass and force constant with respect to oxygen atom. From the band structure it is clear that the top of the valence band is due to thalliumstates, whereas the bottom of the conduction band is due to halogenand oxygenstates, showing similar magnitude of dispersion and exhibits a charge transfer character.
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