Related papers: Quadrupole Orders on the fcc Lattice
We numerically study orders of planer type $(xy,x^2-y^2)$ quadrupoles on a triangular lattice with nearest-neighbor isotropic $J$ and anisotropic $K$ interactions. This type of quadrupoles possesses unique single-ion anisotropy proportional…
We study f-electron lattice models which are capable of supporting octupolar, as well dipolar and quadrupolar, order. Analyzing the properties of the Gamma8 ground state quartet, we find that (111)-type combinations of the Gamma5 octupoles…
We report the results of resonant X-ray scattering experiments performed at the Np M_4,5 edges in NpO_2. Below T_0 = 25 K, the development of long-range order of Np electric quadrupoles is revealed by the growth of superlattice Bragg peaks.…
Motivated by recent experimental suggestions of charge-order-driven ferroelectricity in organic charge-transfer salts, such as $\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]Cl, we investigate magnetic and charge-ordered phases that emerge in an…
We investigate a mechanism of multiple-$q$ states consisting of magnetic dipole and electric quadrupole degrees of freedom in spin-1 triangular-lattice systems. By systematically analyzing a minimal effective multipole model with bilinear…
We report magnetic-field-induced first-order phase transitions in the ferro-quadrupole (FQ) ordered state of PrTi2Al20, in which non-Kramers Pr3+ ions with two 4f electrons have a non-magnetic Gamma3 doublet ground state in the cubic Td…
The antiferromagnetic three-state Potts model on the simple-cubic lattice is studied using Monte Carlo simulations. The ordering in a medium temperature range below the critical point is investigated in detail. Two different regimes have…
We provide thermodynamic evidence for the presence of a magnetic-field-induced small phase pocket near the antiferro-quadrupole (AFQ) phase boundary in the non-Kramers $\Gamma_3$ doublet system PrIr$_2$Zn$_{20}$. In particular, we measured…
Possible order parameters of the phase IV in CexLa1-xB6 are discussed with special attention to the lattice distortion recently observed. A \Gamma_{5u}-type octupole order with finite wave number is proposed as the origin of the distortion…
We study the phase diagram of the three-state Potts model on a triangular lattice with general interactions (ferro/antiferromagnetic) between nearest neighbor spins. When the interactions along two lattice-vector directions are…
Quadrupole ordering with the ordering wavevector at the L points in PrIr$_2$Zn$_{20}$ under magnetic fields is analyzed using classical Monte Carlo simulations based on an effective $\Gamma_3$ quadrupole model on the diamond structure. We…
We report the results of 27Al-NMR measurements on a single crystal of PrTi2Al20. This compound shows a phase transition near 2 K associated with the quadrupole degree of freedom of Pr ions, for which the ground state of the crystalline…
Origin of the non-magnetic phase transition in PrTi$_2$Al$_{20}$, reported earlier in the macroscopic study, has been asserted microscopically using elastic and inelastic neutron scattering techniques. It has been shown spectroscopically…
We study the extended Hubbard model on a two-dimensional half-filled square lattice using the dynamical cluster approximation. We present results on the phase boundaries between the paramagnetic metallic (normal) state and the insulating…
The physical properties of the antiferroquadrupolar state occurring in TmTe below TQ=1.8 K have been studied using neutron diffraction in applied magnetic fields. A field-induced antiferromagnetic component k = (1/2,1/2,1/2) is observed…
Understanding the interplay between topology and ordering in systems on curved manifolds, governed by anisotropic interactions, takes a central role in many fields of physics. In this paper, we investigate the effects of lattice symmetry…
We study by Monte Carlo simulations the effect of quenched orientational disorder in systems of interacting classical dipoles on a square lattice. Each dipole can lie along any of two perpendicular axes that form an angle psi with the…
Toward the understanding of incommensurate $\Gamma_3$ quadrupole ordering in PrPb$_3$, we develop a microscopic theory of multipole ordering in $f^2$-electron systems from an itinerant picture on the basis of a $j$-$j$ coupling scheme. For…
We investigate effects of multipole moments in f-electron systems both from phenomenological and microscopic viewpoints. First, we discuss significant effects of octupole moment on the magnetic susceptibility in a paramagnetic phase. It is…
Phases that go beyond dipolar ordering and into multipolar ordering have recently been observed in magneto-electric materials. The resulting phase diagram is commonly explained using the concept of competing orders and exact microscopic…