Related papers: Theory of the Quantum Paraelectric - Ferroelectric…
Materials tuned to the neighbourhood of a zero temperature phase transition often show the emergence of novel quantum phenomena. Much of the effort to study these new effects, like the breakdown of the conventional Fermi-liquid theory of…
Phase transition between ferroelectricity and quantum paraelectricity via non-thermal tuning parameters can lead to quantum critical behavior and associated emergent phenomena. Ferroelectric quantum critical systems are, however, rare…
The normal ferroelectric to paraelectric phase transition in model ferroelectric materials such as BaTiO3 is typically characterized by a sharp, well-defined dielectric constant peak at a specific transition temperature. However, under…
We present a microscopic model of the quantum paraelectric-ferroelectric phase transition with a focus on the influence of coupled fluctuating phonon modes. These may drive the continuous phase transition first order through a metaelectric…
The temperature dependence of static dielectric susceptibility of a system with strongly coupled fluctuating dipoles is calculated within a self consistent mean fluctuation field approximation. Results are qualitatively in good agreement…
With the development of electronic structure theory, a new class of materials - quantum ones has been recognized by the community. Traditionally, it has been believed that the properties of such compounds cannot be described within the…
Understanding collective phenomena in quantum materials from first principles is a promising route toward engineering materials properties on demand and designing new functionalities. This work examines the quantum paraelectric state, an…
A variety of compounds, for example doped paraelectrics and polar metals, exhibit both ferroelectricity and correlated electronic phenomena such as low-density superconductivity and anomalous transport. Characterizing such properties is…
We demonstrate how the quantum paraelectric ground state of SrTiO$_3$ can be accessed via a microscopic $ab~initio$ approach based on density functional theory. At low temperature the quantum fluctuations are strong enough to stabilize the…
The quantum ferromagnetic transition of itinerant electrons is considered. We give a pedagogical review of recent results which show that zero-temperature soft modes that are commonly neglected, invalidate the standard…
The effect of ferroelectric fluctuations on the temperature dependent dielectric constant of SrTiO$_3\,$(STO) has been long studied. Those fluctuations have been shown in recent years to be quantum critical and STO demonstrated to form the…
Using path-integral Monte Carol simulations and an ab initio effective Hamiltonian, we study the effects of quantum fluctuations on structural phase transitions in the cubic perovskite compounds SrTiO3 and BaTiO3. We find quantum…
Here a recently observed weak first order transition in doped SrTiO3 is argued to be a consequence of the coupling between strain and order parameter fluctuations. Starting with a semi-microscopic action, and using renormalization group…
Zero-temperature or quantum phase transitions in itinerant electronic systems both with and without quenched disordered are discussed. Phase transitions considered include, the ferromagnetic transition, the antiferromagnetic transition, the…
We present an inexpensive first-principles approach for describing quantum paraelectricity that combines density functional theory (DFT) treatment of the electronic subsystem with quantum mechanical treatment of the ions through solution of…
We study the quantum paraelectric-ferroelectric transition near a quantum critical point, emphasizing the role of temperature as a "finite size effect" in time. The influence of temperature near quantum criticality may thus be likened to a…
Dielectric spectroscopy of $SrTiO_3$ single crystal over a broad range of microwave frequency using quasi $TE_{m,1,1}$ and quasi $TM_{m,1,1}$ modes reveals crystal asymmetry from typical measurement of $Q$-factor, transmission or frequency…
Single-crystalline ferroelectric (FE) perovskites show a large electrocaloric effect at electric field-induced phase transitions, promising for solid-state cooling technologies. However, paraelectric-FE transition temperatures are often too…
A transition in a spheroidal particle from the paraelectric to the ferroelectric phase as well as dynamic susceptibility are studied without approximation in the paraphase. It is assumed that the surface charge is compensated and the…
The emergence of complex and fascinating states of quantum matter in the neighborhood of zero temperature phase transitions suggests that such quantum phenomena should be studied in a variety of settings. Advanced technologies of the future…