Related papers: Microscopic theory of quadrupolar ordering in TmTe
We study quadrupole orders in heavy-fermion compound PrIr$_2$Zn$_{20}$ under magnetic fields on the basis of the Landau theory. Assuming $E_g$ electric quadrupolar orders in the cubic symmetry with the ordering wavenumber at the L points in…
We theoretically study electric quadrupole orders in f-electron systems on the fcc lattice. Qudrupole degrees of freedom $O_{20}$ and $O_{22}$ originate in the non-Kramers doublet ground state $\Gamma_3$ of ion with $f^2$ electron…
We study $\Gamma_3$ quadrupole orders in a face-centered cubic lattice. The $\Gamma_3$ quadrupole moments under cubic symmetry possess a unique cubic invariant in their free energy in the uniform ($q=0$) sector and the triple-q sector for…
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…
Resonant soft x-ray Bragg diffraction at the Tb M4,5 edges and non resonant Bragg diffraction have been used to investigate orbitals in TbB2C2. The Tb 4f quadrupole moments are ordered in zero field below T_N and show a ferroquadrupolar…
Topological and crystalline orders of electrons both benefit from enhanced Coulomb interactions in partially filled Landau levels. In bilayer graphene (BLG), the competition between fractional quantum Hall liquids and electronic crystals…
TmVO$_{4}$ exhibits ferroquadrupolar order of the Tm 4f electronic orbitals at low temperatures, and is a model system for Ising nematicity that can be tuned continuously to a quantum phase transition via magnetic fields along the $c$-axis.…
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…
A series of Pr(TM)$_2$X$_{20}$ (with TM=Ti,V,Rh,Ir and X=Al,Zn) Kondo materials, containing non-Kramers Pr$^{3+}$ $4f^2$ moments on a diamond lattice, have been shown to exhibit intertwined orders such as quadrupolar order and…
Motivated by the time-reversal symmetry breaking signal in muon spin relaxation below a transition temperature without accompanying noticeable magnetic Bragg peaks in $5d^2$ Os double perovskites, a rare ferro-octupolar order was proposed…
The heavy-fermion superconductor CeRh2As2 exhibits a non-superconducting phase transition that precedes the emergence of superconductivity. The nature of the corresponding order parameter remains under debate, with competing proposals…
Characteristics of magnetic transitions in NpTGa$_5$ with T=Co, Ni, Rh are explained in a unified way with use of a crystalline electric field (CEF) model of localized 5$f^4$ electrons. The model takes a CEF doublet and a singlet as local…
We present a theoretical model of the "isostructural" \gamma-\alpha phase transition in Ce which is based on quadrupolar interactions due to coupled charge density fluctuations of 4f electrons and of conduction electrons. Conduction…
We investigate antiferro quadrupole orders in systems with non-Kramers doublet ground state with total angular momentum J=4 in T_d point group symmetry. We demonstrate that a pure O_2^2 antiferro quadrupole order is impossible in general…
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…
e have investigated the magnetic properties of YbRu$_{2}$Ge$_{2}$ by means of magnetic susceptibility $\chi$(T), specific heat C(T) and electrical resistivity $\rho$(T) measurements performed on flux grown single crystals. The Curie-Weiss…
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…
As a possible mechanism of the $\gamma-\alpha$ phase transition in pristine cerium a change of the electronic density from a disordered state with symmetry Fm-3m to an ordered state Pa-3 has been proposed. Here we include on-site and inter-…
In order to investigate multipole ordering in f-electron systems from a microscopic viewpoint, we study the so-called \Gamma_8 models on three kinds of lattices, simple cubic (sc), bcc, and fcc, based on a j-j coupling scheme with…
Ferro-quadrupole (FQ) order in the non-Kramers $\Gamma_3$ doublet system PrTi$_2$Al$_{20}$ has been investigated via angle-resolved measurements of the specific heat, rotational magnetocaloric effect, and entropy, under a rotating magnetic…