Kinetic Spinodal Instabilities in the Mott Transition inV2O3: Evidence from Hysteresis Scaling and Dissipative Phase Ordering

Abstract

We present the first systematic observation of scaling of thermal hysteresis with the temperature scanning rate around an abrupt thermodynamic transition in correlated electron systems. We show that the depth of supercooling and superheating in vanadium sesquioxide (V_{2}O_{3}) shifts with the temperature quench rates. The dynamic scaling exponent is close to the mean field prediction of 2/3. These observations, combined with the purely dissipative continuous ordering seen in "quench-and-hold" experiments, indicate departures from classical nucleation theory toward a barrier-free phase ordering associated with critical dynamics. Observation of critical-like features and scaling in a thermally induced abrupt phase transition suggests that the presence of a spinodal-like instability is not just an artifact of the mean field theories but can also exist in the transformation kinetics of real systems, surviving fluctuations.

Absolute calibration of the latent heat of transition using differential thermal analysis

“…5 (b)] are quite sharp indicating an abrupt phase transition (APT) with a relatively large latent heat and the single phase nature of the material. 22 The latent heat peaks associated with the magnetoelastic transition in Ba 3 BiRu 2 O 9 and martensitic transformation in Mn-NiSn alloy, on the other hand, are relatively small. 27,28 The noise in the DTA peaks in Fig.…”

“…7, we had previously observed that the depth of supercooling and superheating increases with the temperature scan rate R, and follows a dynamical scaling relation ∆T (R) ∝ R Υ . 22 Here ∆T (R) = |T j 0 − T j R |, j = H, C, is the shift in the phase transition temperature to an R-dependent value T H R > T H 0 during heating and T C R < T C 0 during cooling. T H 0 and T C 0 are the transition temperature under a quasistatic change in the sample temperature under heating and cooling conditions respectively.…”

Zeroth-Order Nucleation Transition under Nanoscale Phase Separation

“…Metal-insulator phase transitions in some materials, such as V 2 O 3 , were classified as zeroth-order phase transitions, where the free energy is discontinuous [21,22]. These phase transitions exhibit the phase coexistence and ramified fractal-like nanoscale phase separation in the transition region [21][22][23].…”

Zeroth-Order Nucleation Transition under Nanoscale Phase Separation

“…Metal-insulator phase transitions in some materials, such as V 2 O 3 , were classified as zerothorder phase transitions, where the free energy is discontinuous [21,22]. These phase transitions exhibit the phase coexistence and ramified fractal-like nanoscale phase separation in the transition region [21][22][23].…”