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Oxygen isotope effect in VO2

Published on March 28, 2023

We investigate the oxygen isotope effect on the VO2 metal-insulator transition. Using an alternative method, we synthesize V16O2 and V18O2 crystals, finding a 1%–3% phonon softening and a 1.3 K increase in the metal-insulator transition temperature for the latter. A simple calculation, further confirmed by density functional theory, shows that this shift can be attributed to changes in the lattice internal energy. Our results show that lattice dynamics plays a key role in setting the electronic transition temperature, indicating that electronic and structural degrees of freedom remain strongly coupled at the transition.

Authors

Carl Willem Rischau, Xu He, Giacomo Mazza, Stefano Gariglio, Jean-Marc Triscone, Philippe Ghosez, and Javier del Valle