Related papers: Finite temperature second harmonic generation in K…
We develop a finite-temperature perturbation theory for quasi-one-dimensional quantum spin systems, in the manner suggested by H.J. Schulz (1996) and use this formalism to study their dynamical response. The corrections to the random-phase…
The excitations in the Kitaev spin liquid (KSL) can be described by Majorana fermions, which have characteristic field dependence of bulk gap and topological edge modes. In the high-field state of layered honeycomb magnet $\alpha$-RuCl$_3$,…
We reveal the crucial effect of strong spin-charge coupling on high-harmonic generation (HHG) in Mott insulators. In a system with antiferromagnetic correlations, the HHG signal is drastically enhanced with decreasing temperature, even…
In this work we study the phase diagram of Kekul\'{e}-Kitaev model. The model is defined on a honeycomb lattice with bond dependent anisotropic exchange interactions making it exactly solvable in terms of Majorana representation of spins in…
We theoretically study the high-harmonic generation (HHG) in one-dimensional spin systems. While in electronic systems the driving by AC electric fields produces radiation from the dynamics of excited charges, we consider here the situation…
The spin-1/2 quantum Heisenberg model is studied in all spatial dimensions d by renormalization-group theory. Strongly asymmetric phase diagrams in temperature and antiferromagnetic bond probability p are obtained in dimensions d \geq 3.…
The physics of the strongly interacting Hubbard chain (with $t/U \ll 1$) at finite temperatures undergoes a crossover to a spin incoherent regime when the temperature is very small relative to the Fermi energy, but larger than the…
The magnetic and magnetotransport properties of metallic 1$T$-VTe$_{2}$ single crystals were investigated at temperatures from 1.3 to 300 K and in magnetic fields up to 35 T. Upon applying a high magnetic field, it is found that the…
The kinetic excitation of ideal magnetohydrodynamic (MHD) discrete Alfven eigenmodes in the second MHD ballooning stable domain is studied in the presence of a thermal ion temperature gradient (ITG), using linear gyrokinetic…
We report field and temperature dependent measurements of the thermoelectric power (TEP) across the pseudo-metamagnetic transition (MMT) in CeRu$_2$Si$_2$. We applied the thermoelectric gradient parallel and perpendicular to the field along…
Magnetic properties of the ferrimagnetic mixed spin-(1/2,S) Heisenberg chains are examined using quantum Monte Carlo simulations for two different quantum spin numbers S = 1 and 3/2. The calculated magnetization curves at finite…
We provide evidence for a finite temperature ferromagnetic transition in 2-dimensions as $H \to 0$ in thin films of $^3$He on graphite, a model system for the study of two-dimensional magnetism. We perform pulsed and CW NMR experiments at…
The study of the ground state of spinless fermions in 2d disordered clusters (Phys. Rev. Lett. {\bf 83}, 1826 (1999)) has suggested the existence of a new quantum phase for intermediate Coulomb energy to kinetic energy ratios $r_s$. Exact…
The honeycomb Kitaev model describes a $Z_2$ spin liquid with topological order and fractionalized excitations consisting of gapped $\pi$-fluxes and free Majorana fermions. Competing interactions, even when not very strong, are known to…
A novel method invented to measure the minute thermodynamic spin magnetization of dilute two dimensional fermions is applied to electrons in a silicon inversion layer. Interplay between the ferromagnetic interaction and disorder enhances…
We study thermodynamic behaviors of the antiferromagnetic zigzag spin chain in magnetic fields, using the density-matrix renormalization group method for the quantum transfer matrix. We focus on the thermodynamics of the system near the…
The description and detection of unconventional magnetic states such as spin liquids is a recurring topic in condensed matter physics. While much of the efforts have traditionally been directed at geometrically frustrated antiferromagnets,…
We report on spectroscopy study of elementary magnetic excitations in an Ising-like antiferromagnetic chain compound SrCo$_2$V$_2$O$_8$ as a function of temperature and applied transverse magnetic field up to 25 T. An optical as well as an…
The low-temperature magnetic phase diagram of the multiferroic system FeTe$_2$O$_5$Br down to 300 mK and up to 9 T is presented. Short-range magnetic correlations within the crystal layers start to develop already at $\sim$50 K, i.e., far…
Broken symmetries and electronic topology are nicely manifested together in the second order nonlinear optical responses from topologically nontrivial materials. While second order nonlinear optical effects from the electric dipole (ED)…