相关论文: Interpreting Stone's model of Berry Phases
Resistivity measurements are widely exploited to uncover electronic excitations and phase transitions in metallic solids. While single crystals are preferably studied to explore crystalline anisotropies, these usually cancel out in…
A four-state model is proposed for description of the sequence of phase transitions in ferroelectric crystals of DMAGaS and DMAAlS type. The ordering processes in the subsystems of DMA groups are considered as a main reason of such…
We consider a model of bosons on a regular lattice with a kinetic energy due to hopping among sites and a potential energy due to strong on site interaction. A superfluid phase is expected when the ground state of the local energy is doubly…
Using the formalism of pseudospin and isospin operators the Hamiltonian of an effective Kugel-Khomskii model with spin-orbit coupling is derived with an exact account of the $t_{2g}$ multiplet splitting by the crystal field. An analytical…
We study a continuous quasi-two-dimensional order-disorder phase transition that occurs in a simple model of a material that is inhomogeneously strained due to the presence of dislocation lines. Performing Monte Carlo simulations of…
This letter addresses basic questions concerning ferroelectric order in positionally disordered dipolar materials. Three models distinguished by dipole vectors which have one, two or three components are studied by computer simulation.…
The theoretical identification of crystalline topological materials has enjoyed sustained success in simplified materials models, often by singling out discrete symmetry operations protecting the topological phase. When band structure…
The complete irreducible co-representations of the paramagnetic space group provide a simple and direct path to explore the symmetry restrictions of magnetically driven ferroelectricity. The method consists of a straightforward…
We establish an intriguing connection between quantum phase transitions and bifurcations in the reduced fidelity between two different reduced density matrices for quantum lattice many-body systems with symmetry-breaking orders. Our finding…
The confluence of quantum mechanics and complexity, which leads to the emergence of rich, exotic states of matter, motivates the extension of our concepts of quantum ordering. The twin concepts of spontaneously broken symmetry, described in…
We study ground state properties of periodic Anderson model in a two-dimensional square lattice with variational Monte Carlo method. It is shown that there are two different types of quantum phase transition: a conventional…
A treatment of many-electron polar and $s-d(f)$ exchange models is carried out in connection with the development of the theory of magnetism of transition and rare-earth metals, as well as their compounds. Particular emphasis is placed on…
Hyperfine interactions couple nuclear and electronic degrees of freedom. The present work explores how hyperfine coupling within the Tm ions in TmVO$_4$ single crystals affects an electronic ferroquadrupole ordered ground state and its…
It is shown that the Landau paradigm based upon both the quasiparticle concept and the notion of the order parameter is valid and can be used to explain the anomalous behavior of the heavy fermion metals near quantum critical points. The…
A large class of quantum phase transitions for quantum lattice systems are characterized by local order parameters. It is shown that local order parameters may be systematically constructed from tensor network representations of quantum…
In the area of topological and geometric treatment of phase transitions and symmetry breaking in Hamiltonian systems, in a recent paper some general sufficient conditions for these phenomena in $\mathbb{Z}_2$-symmetric systems (i.e.…
We consider the spectral and dynamical properties of quantum systems of $n$ particles on the lattice $\Z^d$, of arbitrary dimension, with a Hamiltonian which in addition to the kinetic term includes a random potential with iid values at the…
The modern theory of orbital magnetization (OM) was developed by using Wannier function method, which has a formalism similar with the Berry phase. In this manuscript, we perform a numerical study on the fate of the OM under disorder, by…
A model of two-species bosons moving on the sites of a lattice is studied at nonzero temperature, focusing on magnetic order and superfluid-insulator transitions. Firstly, Landau theory is used to find the general structure of the phase…
The heavy fermion properties are reviewed on selected examples often studied in Grenoble. The physical problems are presented as example of exotic matter at low temperature with three major insights: the localisation of the 4f electrons,…