Related papers: The nature of the tensor order in Cd2Re2O7
The ferro-rotational order, whose order parameter (OP) is an axial vector invariant under both time reversal (TR) and spatial inversion (SI) operations, is the last remaining category of ferroics to be observed after the ferroelectric,…
MnBi2Te4 is a van der Waals topological insulator with intrinsic intralayer ferromagnetic exchange and A-type antiferromagnetic interlayer coupling. Theoretically, it belongs to a class of structurally centrosymmetric crystals whose layered…
We have studied long range orders of electric quadrupole moments described by an effective pseudospin-$\frac{1}{2}$ Hamiltonian representing pyrochlore magnets with non-Kramers ions under [111] magnetic field, in relevance to…
We review current attempts to characterize the underlying nature of the hidden order in $URu_2Si_2$. A wide variety of experiments point to the existence of two order parameters: a large primary order parameter of unknown character which…
Neutron diffraction studies have been carried out in the applied magnetic field H(//[011]) on a single crystal of pyrochlore ferromagnet Nd2Mo2O7, whose Hall resistivity(r_H) has been reported to have quite unusual magnetic field (H)- and…
The transition metal dichalcogenide 6R-TaS$_{2}$ offers a natural platform for studying the interplay among charge density wave (CDW) order, superconductivity, and transport anomalies. Recent findings reveal that, in the intermediate…
The large N_c N=4 gauge theory with quenched N=2 quark matter displays chiral symmetry breaking in the presence of a magnetic field. We previously studied the temperature and chemical potential phase structure of this theory in the grand…
Second harmonic generation (SHG) is a powerful optical tool for identifying non-centrosymmetric crystalline structures. Here, we analyze SHG in multilayer graphenes (MLG), with a focus on its dependence on the stacking order, encapsulation…
We analytically investigate the effect of a non-centrosymmetric geometry in the optical second harmonic (SH) generation from a particle made of a centrosymmetric material, in the interior of which quadratic optical processes are suppressed.…
The notion of spontaneous symmetry breaking has been used to describe phase transitions in a variety of physical systems. In crystalline solids, the breaking of certain symmetries, such as mirror symmetry, is difficult to detect…
We performed an ultrasonic measurement for the heavy-fermion compound CeRhIn$_5$ to investigate the origin of the field-induced anisotropic phase in high magnetic fields. The transverse elastic constant $C_\mathrm{T} = (C_{11} - C_{12})/2$…
Strong electron interactions can drive metallic systems toward a variety of well-known symmetry-broken phases, but the instabilities of correlated metals with strong spin-orbit coupling have only recently begun to be explored. We uncovered…
We discuss predominant order parameters for structural chirality, and demonstrate that time-reversal-even axial-quadrupole plays a key role in stabilizing a chiral structure. Using the symmetry-adapted closest Wannier model of the trigonal…
Low-temperature powder neutron diffraction measurements are performed in the ordered magnetic state of the pyrochlore antiferromagnet Gd2Sn2O7. Symmetry analysis of the diffraction data indicates that this compound has the ground state…
We propose a chiral charge (electric toroidal monopole) as the hidden order parameter in URu$_{2}$Si$_{2}$, which satisfies all the symmetry conditions accumulated by many experimental and theoretical efforts since its discovery. By using…
Motivated by the search for type-II multiferroics, we present a comprehensive optical study of a complex oxide family of type-II multiferroic candidates: RbFe(MoO4)2, RbFe(SeO4)2, and RbFe(SO4)2. We employ rotational-anisotropy second…
We review and extend a previous study on the symmetry of the superconducting state, stimulated by recent tunneling and Andreev reflection measurements giving robust evidences for the existence of a $d_{x^2-y^2}+id_{xy}$ order parameter in…
We report on the experimental and theoretical investigation of magnetic-field-induced second harmonic generation (SHG) and two-photon absorption (TPA) of excited exciton states ($n \geq 3$) of the yellow series in Cu$_2$O. In this…
The tetragonal compound YbRu$_{2}$Ge$_{2}$ exhibits a non-magnetic transition at $T_0$=10.2K and a magnetic transition at $T_1$=6.5K in zero magnetic field. We present a model for this material based on a quasi-quartet of Yb$^{3+}$…
LMTO calculations are presented for the frequency dependent second harmonic generation (SHG) in the polytypes 2H, 4H, 6H, 15R and 3C of SiC. All independent tensor components are calculated. The spectral features and the ratios of the 333…