First-principles re-investigation of bulk WO3
CIC nanoGUNE Seminars
- Speaker
-
Hanen Hamdi, Theory Group
- When
-
2015/04/20
13:00 - Place
- nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
- Add to calendar
- iCal
Tungsten trioxide WO3 has been extensively studied because of its attractive
photo-electrochromic properties that are widely used in technological
applications such as smart glasses, energy-efficient windows, antiglare
automobile rear-view mirrors, sunroofs, water splitting batteries, photo-
anodes, etc. Most of these properties are related to a rich and complex phase
diagram when cooling or doping WO3. From 1200 K down to 0K, bulk WO3 exhibits
13 structural phase transitions involving antiferroelectric,
antiferrodistortive and ferroelectric structural distortions. In spite of the
numerous studies, the mechanism of these phase transitions is still not fully
understood and particularly the low temperature ferroelectric phase. Here we
re-explore the phase diagram of bulk WO3 from first-principles calculations by
using hybrid functionals (B1WC) and we show that the low temperature phases
are driven by complex high order (improper) couplings between different phonon
modes, which make WO3 very attracting for building multifunctional
superlattices.