Related papers: Non-Loudon-Fleury Raman scattering in spin-orbit c…
We studied the pressure dependence of the room-temperature infrared reflectivity of (TMTTF)_2AsF_6 along all three optical axes. This anisotropic organic compound consists of molecular stacks with orbital overlap along the a direction; due…
Unconventional peak structure in the Raman spectra due to magnon excitation at low temperature is observed in spinel magnet ${\rm MnV_2O_4}$, where a noncollinear spin state is realized by geometrical frustration. We propose a new mechanism…
Motivated by exploring correlated metals with frustrating bond-dependent exchange interactions, we study hole and electron doped Kitaev Mott insulators on the triangular lattice. Using homogeneous parton mean field theory, we find that the…
Na$_2$IrO$_3$, a honeycomb 5$d^5$ oxide, has been recently identified as a potential realization of the Kitaev spin lattice. The basic feature of this spin model is that for each of the three metal-metal links emerging out of a metal site,…
In the search for experimental realizations of bond-anisotropic Kitaev interactions and resulting spin-liquid phases, the layered magnet $\alpha$-RuCl$_3$ is a prime candidate. Its modelling typically involves Heisenberg, Kitaev, and…
Finding new materials with antiferromagnetic (AFM) Kitaev interaction is an urgent issue to broaden and enrich the quantum magnetism research significantly. By carrying out inelastic neutron scattering experiments and subsequent analysis,…
We investigate the experimental signatures of Raman spectroscopy of bi- and tri-magnon excitations in the distorted triangular lattice antiferromagnets alpha-LCr2O4 (L=Sr, Ca). We utilize spin wave theory to analyze the nearly 120 degree…
We report on a new electromagnetic phenomenon that emerges in Mott insulators, i.e., materials that do not conduct electricity because of strong electronic Coulomb repulsion. The phenomenon manifests as antiferromagnetic ordering due to…
Raman scattering is used to observe pronounced electronic excitations around 230 meV - well above the two-phonon range - in the Mott insulators LaTiO$_3$ and YTiO$_3$. Based on the temperature, polarization, and photon energy dependence,…
Thermomagnetic and inelastic neutron scattering measurements on Na2PrO3 are reported. This material is an antiferromagnetic honeycomb magnet based on the tetravalent lanthanide Pr4+ and has been proposed to host dominant antiferromagnetic…
Several powerful techniques exist to detect topologically protected surface states of weakly-interacting electronic systems. In contrast, surface modes of strongly interacting systems which do not carry electric charge are much harder to…
In RuCl$_3$, inelastic neutron scattering and Raman spectroscopy reveal a continuum of non-spin-wave excitations that persists to high temperature, suggesting the presence of a spin liquid state on a honeycomb lattice. In the context of the…
We study first-order (single-magnon) inelastic light scatterings in spin-$\frac{1}{2}$ two-dimensional quasiperiodic antiferromagnets in comparison with those emergent on periodic lattices. Unlike second-order (two-magnon) Raman scatterings…
We theoretically explore how light-driven optical phonons can be used to drive magnetic exchange interactions into interesting physical regimes by developing a general theory of spin-phonon pumping in magnetic insulators with…
We report structural studies of the spin-orbit Mott insulator family K$_x$Ir$_y$O$_2$, with triangular layers of edge-sharing IrO$_6$ octahedra bonded by potassium ions. The potassium content acts as a chemical tuning parameter to control…
In this paper, we review recent development in the theory of resonant inelastic light (Raman) scattering in one-dimensional electron systems. The particular systems we have in mind are electron doped GaAs based semiconductor quantum wire…
In this study, we reanalyze the magnetic interactions in the Kitaev spin liquid candidate materials Na$_2$IrO$_3$, $\alpha$-RuCl$_3$, and $\alpha$-Li$_2$IrO$_3$ using nonperturbative exact diagonalization methods. These methods are more…
Spin-orbit coupling locks spin direction and spatial orientation and generates, in semi-classical magnets, a local spin easy-axis and associated ordering. Quantum spin-1/2's defy this fate: rather than spins becoming locally anisotropic,…
We propose a theoretical model for a gapless spin liquid phase that may have been observed in a recent experiment on $\mathrm{H_3Li Ir_2 O_6}$. Despite the insulating and non-magnetic nature of the material, the specific heat coefficient…
Recent proposals for spin-1 Kitaev materials, such as honeycomb Ni oxides with heavy elements of Bi and Sb, have shown that these compounds naturally give rise to antiferromagnetic (AFM) Kitaev couplings. Conceptual interest in such AFM…