TY - JOUR
A1 - Miliūtė, Aistė
A1 - Bustamante, Joana
A1 - Karafiludis, Stephanos
A1 - Zöllner, Moritz
A1 - Eddah, Mustapha
A1 - Emmerling, Franziska
A1 - Mieller, Björn
A1 - George, Janine
A1 - Stawski, Tomasz M.
T1 - Synthesis and phase purity of the negative thermal expansion material ZrV2O7
N2 - Synthesis of pure, homogeneous, and reproducible materials is key for the comprehensive understanding, design, and tailoring of material properties. In this study, we focus on the synthesis of ZrV2O7, a material known for its negative thermal expansion properties. We investigate the influence of solid-state and wet chemistry synthesis methods on the purity and homogeneity of ZrV2O7 samples. Our findings indicate that different synthesis methods significantly impact the material's characteristics. The solid-state reaction provided high-purity material through extended milling time and repeated calcination cycles, while the sol-gel reaction enabled a “near-atomic” level of mixing and, therefore, homogenous phase-pure ZrV2O7. We confirmed purity via X-ray diffraction and Raman spectroscopy, highlighting differences between phase-pure and multiphase ceramics. These analytical techniques allowed us to distinguish subtle differences in the structure of the material. Based on ab initio simulated phonon data, we were able to interpret the Raman spectra and visualise Raman active atom vibrations. We show that phase purity enables the unbiased characterisation of material properties such as negative thermal expansion.
KW - NTE
KW - Sol-gel
KW - Solid-state
KW - Ab-initio
KW - XRD
KW - Raman
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624013
DO - https://doi.org/10.1039/d4tc04095c
SN - 2050-7534
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bustamante, Joana
A1 - Ghata, Anupama
A1 - Naik, Aakash A.
A1 - Ertural, Christina
A1 - Ueltzen, Katharina
A1 - Zeier, Wolfgang G.
A1 - George, Janine
T1 - Thermal transport in Ag8T S6(T = Si, Ge, Sn) argyrodites: an integrated experimental, quantum-chemical, and computational modelling study
N2 - Argyrodite-type Ag-based sulfides combine exceptionally low lattice thermal and high ionic conductivity, making them promising candidates for thermoelectric and solid-state energy applications. In this work, we studied Ag8TS6 (T = Si, Ge, Sn) argyrodite family by combining chemical-bonding analysis, lattice vibrational properties simulation, and experimental measurements to investigate their structural and thermal transport properties. Furthermore, we propose a two-channel lattice-dynamics model based on Grüneisen-derived phonon lifetimes and compare it to an approach using machine-learned interatomic potentials. Both approaches are able to predict thermal conductivity in agreement with experimental lattice thermal conductivities along the whole temperature range, highlighting their potential suitability for future high-throughput predictions. Our findings also reveal a relationship between bond heterogeneity arising from weakly bonded Ag+ ions and occupied antibonding states in Ag–S and Ag–Ag interactions and strong anharmonicity, including large Grüneisen parameters, and low sound velocities, which are responsible for the low lattice thermal conductivity of Ag8SnS6, Ag8GeS6, and Ag8SiS6. We furthermore show that thermal and ionic conductivities in all three compounds are independent of each other and can likely be tuned individually.
KW - Thermal Conductivity
KW - Ionic Conductivity
KW - Machine Learning
KW - Materials Design
KW - Microstructure
KW - Bonding Analysis
KW - Anharmonicity
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657076
DO - https://doi.org/10.1039/D5TA08709K
SN - 2050-7488
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -