Related papers: Spin-orbit-enhanced magnetic surface second-harmon…
The currently accepted magnetic ground state of Sr2IrO4 (the -++- state) preserves inversion symmetry. This is at odds, though, with recent experiments that indicate a magnetoelectric ground state, leading to the speculation that orbital…
The interplay between magnetism and light can create abundant optical phenomena. Here, we demonstrate the emergence of an unconventional magnetization-induced second-harmonic generation (MSHG) stemming from vector spin chirality, denoted as…
Sr$_2$CuO$_2$Cl$_2$ (SCOC) is a model undoped cuprate with $I4/mmm$ crystallographic symmetry, and a simple magnetic space group $C_Amca$ with associated magnetic point group $mmm1'$. However, recent second harmonic spectroscopy in the…
Second-harmonic generation (SHG) is a second-order nonlinear optical process that is not allowed in media with inversion sym-metry. However, due to the broken symmetry at the surface, surface SHG still occurs, but is generally small. We…
Second-harmonic generation (SHG) has emerged as a promising tool for detecting electronic and magnetic structures in noncentrosymmetric materials, but 100$\%$ spin-polarized SHG has not been reported. In this work, we demonstrate nearly…
We report a global structural distortion in Sr$_2$IrO$_4$ using spatially resolved optical second and third harmonic generation rotational anisotropy measurements. A symmetry lowering from an $I4_{1}/acd$ to $I4_{1}/a$ space group is…
Spectroscopy of the centrosymmetric magnetic semiconductors EuTe and EuSe reveals spin-induced optical second harmonic generation (SHG) in the band gap vicinity at 2.1-2.4eV. The magnetic field and temperature dependence demonstrates that…
Recent experiments and calculations in topological semimetals have observed anomalously strong second-order optical nonlinearity, but yet whether the enhancement also occurs at surfaces of topological semimetals in general remains an open…
A rare combination of strong spin-orbit coupling and electron-electron correlations makes the iridate Mott insulator Sr$_2$IrO$_4$ a promising host for novel electronic phases of matter. The resemblance of its crystallographic, magnetic and…
The relation between crystal symmetries, electron correlations, and electronic structure steers the formation of a large array of unconventional phases of matter, including magneto-electric loop currents and chiral magnetism. Detection of…
Using symmetry arguments we show how optical second harmonic generation (SHG) can be used to detect antiferromagnetism at surfaces and in thin films. Based on the group theoretical analysis of the nonlinear electric susceptibility we…
We report on the optical second harmonic generation (SHG) on the 1S exciton-polariton resonance in bulk ZnSe that is subject to an external magnetic field applied perpendicular to the light wave vector $\mathbf k$ (Voigt geometry). For the…
We theoretically investigate the second harmonic generation (SHG) of topological insulator surface states in a perpendicular magnetic field. Our theory is based on the microscopic expression of the second-order magneto-optical conductivity…
Recently Second Harmonic Generation (SHG) for the yellow exciton series in cuprous oxide has been demonstrated [J. Mund et al., Phys. Rev. B 98, 085203 (2018)]. Assuming perfect $O_{\mathrm{h}}$ symmetry, SHG is forbidden along certain…
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…
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…
Correlated materials with competing spin-orbit and crystal-field interactions can host composite spin-orbital magnons that are highly susceptible to structural and electronic perturbations, enabling the control of magnetic dynamics beyond…
A comprehensive analysis of optical second harmonic generation (SHG) on an incommensurate (IC) magnetically ordered state is presented using multiferroic MnWO4 as model compound. Two fundamentally different SHG contributions coupling to the…
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)…
The Hall effect in SrRuO$_3$ thin-films near the thickness limit for ferromagnetism shows an extra peak in addition to the ordinary and anomalous Hall effects. This extra peak has been attributed to a topological Hall effect due to…