dc.creatorCoak, Matthew J.
dc.creatorHaines, Charles Robert Sebastian
dc.creatorLiu, Cheng
dc.creatorGuzmán Verri, Gian Giacomo
dc.creatorSaxena, Siddharth S.
dc.date.accessioned2020-01-30T14:42:11Z
dc.date.accessioned2022-10-20T02:09:16Z
dc.date.available2020-01-30T14:42:11Z
dc.date.available2022-10-20T02:09:16Z
dc.date.created2020-01-30T14:42:11Z
dc.date.issued2019-12-13
dc.identifierhttps://link.aps.org/doi/10.1103/PhysRevB.100.214111
dc.identifier2469-9950
dc.identifier2469-9969
dc.identifierhttps://hdl.handle.net/10669/80394
dc.identifier10.1103/PhysRevB.100.214111
dc.identifier816-B7-601
dc.identifier.urihttps://repositorioslatinoamericanos.uchile.cl/handle/2250/4545330
dc.description.abstractPhase transitions to a long-range-ordered state driven by a softened phonon mode are ubiquitous across condensed matter physics, but the evolution of such a mode as the system is tuned to or from the transition has never been explicitly measured until now. We report the effect of pressure on the soft mode associated with ferroelectricity in the archetypal quantum critical paraelectric SrTiO3. This is an ideal, clean, model system for exploring these effects, with pressure directly addressing the phonon modes only. We measure and report the effect of quantum critical fluctuations on the pressure and temperature dependence of the ferroelectric soft phonon mode as the system is tuned away from criticality. We show that the mean-field approximation is confirmed experimentally. Furthermore, using a self-consistent model of the quantum critical excitations including coupling to the volume strain and without adjustable parameters, we determine logarithmic corrections that would be observable only very close to the quantum critical point. Thus, the mean-field character of the pressure dependence is much more robust to the fluctuations than is the temperature dependence. We predict stronger corrections for lower dimensionalities. The same calculation confirms that the Lydanne-Sachs-Teller relation is valid over the whole pressure and temperature range considered. Therefore, the measured dielectric constant can be used to extract the frequency of the soft mode down to 1.5 K and up to 20 kbar of applied pressure. The soft mode is observed to stiffen further, raising the low-temperature energy gap and returning towards the expected shallow temperature dependence of an optical mode. This behavior is consistent with the existence of a ferroelectric quantum critical point on the pressure-temperature phase diagram of SrTiO3, which applied pressure tunes the system away from. This work represents an experimental measurement of the stiffening of a zone center soft phonon mode as a system is tuned away from criticality, a potentially universal phenomenon across a variety of phase transitions and systems in condensed matter physics.
dc.languageen_US
dc.sourcePhysical Review B, 100, 214111
dc.subjectFerroelectricity
dc.titlePressure dependence of ferroelectric quantum critical fluctuation
dc.typeartículo científico
dc.typeversión final del autor


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