Programme

P.50 -- Posters, VCTP-50

Date: Tuesday, 5 August 2025

Time: 08:30 - 10:00

Emergent Localized Electronic States and Phonon Suppression in V_2WO_6: A New Class of Oxide Thermoelectric Materials

Le Nguyen Ngoc Quy (1,2,3), Vu Hoang Nam (1,2,3), Tran Quang Minh Nhat (1,2,3)

(1) Faculty of Materials Science and Technology, University of Science, Hochiminh City, Vietnam; (2) Center for Innovative Materials and Architectures (INOMAR), Hochiminh City, Vietnam; (3) Vietnam National University, Hochiminh City, Vietnam

We present a comprehensive theoretical and experimental investigation of V_2WO_6, an oxide that couples Anderson-like electronic localization with strong phonon scattering to enable promising thermoelectric performance. Density-functional theory and transport measurements show that electronic conduction is strongly influenced by localized states near the Fermi level, consistent with Anderson localization and Mott-type correlations within vanadium $d$-orbitals. This coexistence of itinerant and localized carriers preserves a large Seebeck coefficient ($\sim -395\ \mu\mathrm{V,K^{-1}}$ at 300 K). Phonon‐dispersion spectra reveal softened acoustic modes and extensive acoustic–optical coupling, driving intrinsic phonon-glass behavior. Consequently, the total thermal conductivity remains as low as $\sim 0.9\ \mathrm{W,m^{-1},K^{-1}}$ over a wide temperature range, falling to a lattice component of $\sim 0.18\ \mathrm{W,m^{-1},K^{-1}}$ at high temperatures. These coupled electronic and phononic features yield a peak thermoelectric figure of merit $zT \approx 0.42$ at 900 K in pristine polycrystalline samples. V_2WO_6 thus emerges as a prototype for designing oxide thermoelectrics that harness correlated electronic localization alongside engineered phonon suppression, offering a fresh pathway toward high-performance, thermally robust energy-conversion materials.

Presenter: Le Nguyen Ngoc Quy