A5020076237- Advanced Thermoelectric Materials and Devices
- Topological Materials and Phenomena
- Chalcogenide Semiconductor Thin Films
- Thermal properties of materials
- 2D Materials and Applications
- Advanced Condensed Matter Physics
- Graphene research and applications
- Quantum, superfluid, helium dynamics
- Physics of Superconductivity and Magnetism
- High-pressure geophysics and materials
- Perovskite Materials and Applications
- Phase-change materials and chalcogenides
- Magnetic properties of thin films
- Thermal Expansion and Ionic Conductivity
- Mechanical and Optical Resonators
- Magnetic and transport properties of perovskites and related materials
- Thermal Radiation and Cooling Technologies
- Solar-Powered Water Purification Methods
- Quantum many-body systems
- Quantum Dots Synthesis And Properties
- Nanotechnology research and applications
- Iron-based superconductors research
- Chemical Thermodynamics and Molecular Structure
- Perfectionism, Procrastination, Anxiety Studies
- Heusler alloys: electronic and magnetic properties
Indian Institute of Science Education and Research, Bhopal
2024-2025
Max Planck Institute for Chemical Physics of Solids
2021-2025
Jawaharlal Nehru Centre for Advanced Scientific Research
2015-2023
Bangalore University
2015-2018
Ordering up better conductivity Improving a thermoelectric material's ability to convert heat electricity involves optimizing one property without changing another in detrimental way. Roychowdhury et al. found that cadmium doping of silver antimony telluride enhances cationic ordering, which simultaneously improves electric properties and helpfully decreases thermal (see the Perspective by Liu Ibáñez). This strategy markedly could be used for other materials. Science , this issue p. 722 ;...
High thermoelectric figure of merit, zT, ∼1.85 at 725 K along with significant cyclable temperature stability was achieved in Pb-free p-type Ge1–xSbxTe samples through simultaneous enhancement Seebeck coefficient and reduction thermal conductivity. Sb doping GeTe decreases the carrier concentration due to donor dopant nature enhances valence band degeneracy by increasing cubic sample, which collectively boost range 300–773 K. Significant conductivity collective phonon scattering from various...
This review summarizes the past and recent developments in thermoelectric properties, nano/microstructure modulations, mechanical thermal stability of GeTe based materials devices on GeTe.
Metavalent bonding has attracted immense interest owing to its capacity impart a distinct property portfolio materials for advanced functionality. Coupling metavalent lone pair expression can be an innovative way propagate lattice anharmonicity from pair-induced local symmetry-breaking via the soft p-bonding electrons achieve long-range phonon dampening in crystalline solids. Motivated by shared chemical design pool topological quantum and thermoelectrics, we based our studies on...
Nano/meso-structuring reduces the thermal conductivity in Ge<sub>1−x</sub>Bi<sub>x</sub>Te samples, which results a thermoelectric figure of merit, <italic>zT</italic>, 1.3 Ge<sub>1−x</sub>Bi<sub>x</sub>Te.
Thermoelectric materials can convert untapped heat to electricity and are expected have an important role in future energy utilization. IV–VI metal chalcogenides the most promising candidates for mid-temperature thermoelectric power generation. Among them, PbTe their alloys been proven be superior materials. Unfortunately, toxicity of lead (Pb) prevents application demands search lead-free high-performance solids. This perspective discusses recent progress property studies on germanium...
The orthorhombic phase of GeSe, a structural analogue layered SnSe (space group: Pnma), has recently attracted attention after theoretical prediction high thermoelectric figure merit, zT > 2. experimental realization such performance in however, is still elusive (zT ≈ 0.2). rhombohedral GeTe R3m), previously stabilized at pressure (2 GPa) and temperature (1600 K), promising due to its theoretically predicted ferroelectric instability the higher earth abundance Se compared Te. Here, we...
Lead chalcogenides and their alloys belong at the heart of thermoelectrics due to large thermoelectric figure merit (zT). However, recent research has shown a limitation in use lead (Pb)-based materials toxicity efforts have been made produce non-toxic analogues chalcogenides. Tin predicted be promising for this purpose unique electronic structure phonon dispersion properties. Here, we discuss journey tin field topological with main emphasis on bonding, crystal structures, band The thermal...
The realization of n-type Ge chalcogenides is elusive owing to intrinsic vacancies that make them p-type semiconductors. GeSe crystallizes into a layered orthorhombic structure similar SnSe at ambient conditions. high-symmetry cubic phase predicted be stabilized by applying 7 GPa external pressure or enhancing the entropy increasing temperature 920 K. Stabilization conditions was achieved alloying with AgBiSe2 (30-50 mol %), through solid solution mixing. interplay positive and negative...
High-performance thermoelectric materials are desirable in the lower-medium temperature range (450–650 K) for low-grade waste heat recovery. We report a figure of merit (zT) 1.9 at 585 K p-type AgSb1–xZnxTe2, which is highest value measured among 450–650 range. A high average (zTavg) 1.3 achieved AgSb0.96Zn0.04Te2. Moreover, AgSb1–xZnxTe2 sample exhibits hardness ∼6.3 GPa (nanoindentation), significantly higher than that pristine AgSbTe2. Substitution Zn AgSbTe2 suppresses formation...
Abstract Crystalline solids with intrinsically low lattice thermal conductivity (κ L ) are crucial to realizing high‐performance thermoelectric (TE) materials. Herein, we show an ultralow κ of 0.35 Wm −1 K in AgCuTe, which has a remarkable TE figure‐of‐merit, zT 1.6 at 670 when alloyed 10 mol % Se. First‐principles DFT calculation reveals several soft phonon modes its room‐temperature hexagonal phase, also evident from low‐temperature heat‐capacity measurement. These modes, dominated by Ag...
Understanding of phase stability, chemical bonding, and phonon transport are essential to realize ultralow thermal conductivity in crystalline solids for designing high-performance thermoelectric (TE) materials. Pristine SnTe, a homologue PbTe, exhibits poor TE performance primarily because high lattice conductivity, κlat. Herein, the amorphous limit κlat is achieved via engineering configurational vibrational entropies pseudoternary (SnTe)1–2x(SnSe)x(SnS)x. Density functional theory...
A two-step optimization strategy is used to improve the thermoelectric performance of SnTe via modulating electronic structure and phonon transport. The electrical transport self-compensated (that is, Sn1.03 Te) was first optimized by Ag doping, which resulted in an carrier concentration. Subsequently, Mn doping Sn1.03-x Agx Te highly converged valence bands, improved Seebeck coefficient. energy gap between light heavy hole i.e. ΔEv decreases 0.10 eV Sn0.83 Ag0.03 Mn0.17 compared value 0.35...
Abstract Orthorhombic GeSe is a promising thermoelectric material. However, large band gap and strong covalent bonding result in low figure of merit, zT ≈0.2. Here, we demonstrate maximum ≈1.35 at 627 K p ‐type polycrystalline rhombohedral (GeSe) 0.9 (AgBiTe 2 ) 0.1 , which the highest value reported among based materials. The phase stable ambient conditions for x =0.8–0.29 1− . structural transformation accompanies change from orthorhombic to metavalent has closely lying primary secondary...
Thermoelectric (TE) energy conversion demands high performance crystalline inorganic solids that exhibit ultralow thermal conductivity, mechanical stability, and good TE device properties. Pb-free germanium telluride (GeTe)-based material has recently attracted significant attention in power generation mid temperatures, but pristine GeTe possesses significantly higher lattice conductivity (κ
The highly enhanced thermoelectric figure of merit, zT ≈ 2.6 at 573 K, obtained recently in Cd-doped polycrystalline AgSbTe2 by Roychowdhury et al. ( Science 2021, 371, 722) brings it to the forefront and energy materials research. Ag/Sb cationic ordering was a challenging issue for long time: their ordered arrangement sublattice samples remained elusive despite multiple theoretical predictions experimental studies. Recently, selective cation doping has been used enhance ordering, nanoscale...
Kagome magnets possess several novel nontrivial topological features owing to the strong correlation between topology and magnetism that extends their applications in field of thermoelectricity. Conventional thermoelectric (TE) devices use Seebeck effect convert heat into electrical energy. In contrast, transverse based on Nernst are attracting recent attention due unique geometry, which uses a single material eliminate need for multitude connections compared conventional TE devices. Here,...
Abstract Weyl semimetal is a unique topological phase with topologically protected band crossings in the bulk and robust surface states called Fermi arcs. nodes always appear pairs opposite chiralities, they need to have either time‐reversal or inversion symmetry broken. When broken minimum number of points (WPs) two. If these WPs are located at level, form an ideal (WSM). In this study, intrinsic ferromagnetic (FM) EuCd 2 As grown, predicted be WSM studied its electronic structure by...
Compounds with kagome lattice structure are known to exhibit Dirac cones, flatbands, and van Hove singularities, which host numerous versatile quantum phenomena. Inspired by these intriguing properties, we investigate the temperature magnetic field-dependent electrical transports along theoretical calculations of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>ScV</a:mi><a:mn>6</a:mn></a:msub><a:msub><a:mi>Sn</a:mi><a:mn>6</a:mn></a:msub></a:mrow></a:math>, a...
Waste heat sources are generally diffused and provide a range of temperatures rather than particular temperature. Thus, thermoelectric waste to electricity conversion requires high average figure merit (ZTavg ) materials over the entire working temperature along with peak (ZTmax ). Herein an ultrahigh ZTavg 1.4 for (GeTe)80 (AgSbSe2 )20 [TAGSSe-80, T=tellurium, A=antimony, G=germanium, S=silver, Se=selenium] is reported in 300-700 K, which one highest values measured amongst state-of-the-art...
Remarkable enhancement of the Seebeck coefficient an Sn rich Sn<sub>1−x</sub>Pb<sub>x</sub>Te system due to synergistic effect resonance level formation and valence band convergence.
Abstract Topological crystalline insulators (TCIs) are a new quantum state of matter in which linearly dispersed metallic surface states protected by crystal mirror symmetry. Owing to its vanishingly small bulk band gap, TCI like Pb 0.6 Sn 0.4 Te has poor thermoelectric properties. Breaking symmetry can widen the gap TCI. While breaking been mostly explored various physical perturbation techniques, chemical doping, may also alter electronic structure perturbing local symmetry, not yet...