Related papers: Generalized Cubic Model for BaTiO$_3$-like Ferroel…
The lattice instabilities of perovskite structure oxides are responsible for many of their interesting properties, such as temperature-dependent ferroelectric phase transitions. First-principles calculations using linear response theory…
The ferroelectric phase transition in barium titanate under pressure was studied within the framework of Landau-Ginzburg theory using differential scanning calorimetry. An innovative method for high-sensitive thermal measurements under…
The magnetic and nematic properties of the iron chalcogenides have recently been the subject of intense interest. Motivated by the proposed antiferroquadrupolar and Ising-nematic orders for the bulk FeSe, we study the phase diagram of an…
The functional defined as the squared modulus of the spatial average of the wave function squared, plays the role of an ``order parameter'' for the transition between Hamiltonian ensembles with orthogonal and unitary symmetry. Upon breaking…
"Hidden phases" are metastable collective states of matter that are typically not accessible on equilibrium phase diagrams. These phases can host exotic properties in otherwise conventional materials and hence may enable novel functionality…
A first-principles investigation of cubic-BaRuO$_3$, by combining density functional theory with dynamical mean-field theory and a hybridization expansion continuous time quantum Monte-Carlo solver, has been carried out. Non-magnetic…
An extension of the Consistent-Q formalism for the Interacting Boson Model that includes the cubic QxQxQ term is proposed. The potential energy surface for the cubic quadrupole interaction is explicitly calculated within the coherent state…
Ferroelectric polar displacements have recently been observed in conducting electron-doped BaTiO3. The co-existence of a ferroelectric phase and conductivity opens the door to new functionalities which may provide a unique route for novel…
The majority of magnetoelectric crystals show complex temperature-magnetic field or temperature-pressure phase diagrams with alternating antiferromagnetic incommensurate, magnetoelectric, and commensurate phases. Such phase diagrams occur…
We have used first-principles methods to investigate the phase diagram of multiferroic bismuth ferrite (BiFeO3 or BFO), revealing the energetic and vibrational features that control the occurrence of various relevant structures. More…
Ordered phases of matter, such as solids, ferromagnets, superfluids, or quantum topological order, typically only exist at low temperatures. Despite this conventional wisdom, we present explicit local models in which all such phases persist…
The thermodynamically stable long-range orbital order in bulk LaMnO3 becomes metastable at nanoscale around a critical particle size d_C~20 nm. The orbital order-disorder transition switches from reversible to irreversible at d_C while the…
We use our recently proposed microscopic modeling in the framework of linear response theory to investigate the complete phonon dispersion, the phonon density of states, certain phonon-induced electronic charge distributions and charge…
First principles linear response calculations are used to investigate the lattice dynamics of what is thought to be the third most abundant phase in the lower mantle, CaSiO_3 perovskite. The commonly assumed cubic structure (Pm3m) is found…
In the present work ferromagnetic ordering in the Hubbard model generalized by taking into account the inter-atomic exchange interaction and correlated hopping in partially filled narrow band is considered. Expressions for the magnetization…
We study the extended Hubbard model on the triangular lattice as a function of filling and interaction strength. The complex interplay of kinetic frustration and strong interactions on the triangular lattice leads to exotic phases where…
The late-time phase-ordering kinetics of the O(n) model for a non-conserved order parameter are considered for the case where the O(n) symmetry is broken by the initial conditions or by an external field. An approximate theoretical…
In this work we explore the overall structural behaviour of the [(CH3)2NH2][Mn(HCOO)3] multiferroic compound across the temperature range where its ferroelectric transition takes place by means of calorimetry, thermal expansion measurements…
The three-state Potts model is numerically investigated on three-dimensional simple cubic lattices of up to \(128^3\) volume, concentrating on the neighborhood of the first-order phase transition separating the ordered and disordered…
We describe non-equilibrium phase transitions in arrays of dynamical systems with cubic nonlinearity driven by multiplicative Gaussian white noise. Depending on the sign of the spatial coupling we observe transitions to ferromagnetic or…