The origin of the vanadium dioxide transition entropy

Abstract

The reversible metal-insulator transition in VO${}_2$ at $T_{\text{C}}\approx 340$ K has been closely scrutinized yet its thermodynamic origin remains ambiguous. We discuss the origin of the transition entropy by calculating the electron and phonon contributions at $T_{\text{C}}$ using density functional theory. The vibration frequencies are obtained from harmonic phonon calculations, with the soft modes that are imaginary at zero temperature renormalized to real values at $T_{\text{C}}$ using experimental information from diffuse x-ray scattering at high-symmetry wavevectors. Gaussian Process Regression is used to infer the transformed frequencies for wavevectors across the whole Brillouin zone, and in turn compute the finite temperature phonon partition function to predict transition thermodynamics. Using this method, we predict the phase transition in VO${}_2$ is driven five to one by phonon entropy over electronic entropy, and predict a total transition entropy that accounts for $95$ % of the calorimetric value.

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Cited by in corpus (10)

• Unraveling the Mott-Peierls intrigue in Vanadium dioxide
• Unraveling the role of V-V dimer on the vibrational properties of VO${}_2$ by first-principles simulations and Raman spectroscopic analysis
• Importance of ligand on-site interactions for the description of Mott-insulators in DFT+DMFT
• Explicit demonstration of the equivalence between DFT+U and the Hartree-Fock limit of DFT+DMFT
• VO${}_2$ under hydrostatic pressure: Isostructural phase transition close to a critical end-point
• Lattice and Electronic properties of VO${}_2$ with the SCAN(+$U$) approach
• Incorporating static intersite correlation effects in vanadium dioxide through DFT$+V$
• Influence of germanium substitution on the structural and electronic stability of the competing vanadium dioxide phases
• Reversible modulation of metal-insulator transition in VO2 via chemically-induced oxygen migration
• Ultrafast dynamics of atomic correlated disordering in photoinduced VO${}_2$