Related papers: Microscopic model realization of $\boldsymbol{d}$-…
Recent optical second-harmonic generation experiments observed unexpected broken spatial symmetries in the undoped spin-orbit Mott insulator Sr$_2$IrO$_4$, leading to intensive debates on the nature of its ground state. We propose that it…
A polarized electronic Raman scattering study reveals the emergence of symmetry dependence in the electronic Raman response of single crystalline URu$_{2}$Si$_{2}$ below the Kondo crossover scale $T_K\sim100K$. In particular, the…
Protected by the interplay of on-site Coulomb interactions and spin-orbit coupling, Sr$_2$IrO$_4$ at high pressure is a rare example of a Mott insulator with a paramagnetic ground state. Here, using optical Raman scattering, we measure both…
Recent experiments on vanadium-based nonmagnetic kagom\'e metals $A$V$_3$Sb$_5$ ($A=$ K, Rb, Cs) revealed evidence for possible spontaneous time-reversal symmetry (TRS) breaking in the charge density wave (CDW) ordered state. The…
Transformation of Coulomb interaction terms to the pseudo-orbital basis constituted by $J=1/2$ and $3/2$ states arising from spin-orbit coupling provides a versatile tool. This formalism is applied to investigate magnetic anisotropy effects…
The symmetry of the superconducting condensate in Sr$_2$RuO$_4$ remains controversial after nuclear magnetic resonance (NMR) experiments recently overturned the dominant chiral $p$-wave paradigm. Several theoretical proposals have been put…
We investigate a microscopic model for strongly correlated electrons with both on-site and nearest neighbor Coulomb repulsion on a 2D square lattice. This exhibits a state in which electrons undergo a ``somersault'' in their internal…
Scanning tunneling microscopy/spectroscopy is used to examine the $4a$$\times$$4a$ electronic charge order (CO) in the pseudogap (PG) state above {\it T}$_{\rm c}$ on Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$. It is demonstrated that the…
The superconducting symmetry of Sr$_2$RuO$_4$ remains a puzzle. Time-reversal symmetry breaking $d_{x^2-y^2} + ig_{xy(x^2-y^2)}$ pairing has been proposed for reconciling multiple key experiments. However, its stability remains unclear. In…
Layered 5$d$ transition iridium oxides, Sr$_2$(Ir,Rh)O$_4$, are described as unconventional Mott insulators with strong spin-orbit coupling. The undoped compound, Sr$_2$IrO$_4$, is a nearly ideal two-dimensional pseudospin-$1/2$ Heisenberg…
Analogs of the high-T$_c$ cuprates have been long sought after in transition metal oxides. Due to the strong spin-orbit coupling (SOC), the $5d$ perovskite iridates Sr$_2$IrO$_4$ exhibit a low-energy electronic structure remarkably similar…
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…
In the unconventional superconductor Sr$\mathsf{_2}$RuO$\mathsf{_4}$, unusual first-order superconducting transition has been observed in the low-temperature and high-field region, accompanied by a four-fold anisotropy of the in-plane upper…
The anisotropy of the superconducting state and superconducting fluctuations in the CuO2 plane is directly related to the superconducting mechanism of copper oxide superconductors and is therefore pivotal for understanding high-temperature…
We study the low-lying excitations in 5d transition-metal oxide Sr_2IrO_4 on the localized electron picture. We find that Hund's coupling together with the spin-orbit interaction leads to exchange anisotropy which causes the spin wave gap.…
We study spin dynamics of ordered phases of Cs2CoBr4 in a magnetic field using electron spin resonance (ESR) technique and theoretical analysis. This material hosts weakly interacting distorted-triangular-lattice planes of spin-3/2 Co(2+)…
With decreasing temperature Sr$_2$VO$_4$ undergoes two structural phase transitions, tetragonal-to-orthorhombic-to-tetragonal, without long-range magnetic order. Recent experiments suggest, that only at very low temperature Sr$_{2}$VO$_{4}$…
We study the emergence of charge ordered phases within a pi-loop current (piLC) model for the pseudogap based on a three-band model for underdoped cuprate superconductors. Loop currents and charge ordering are driven by distinct components…
Sr$_2$RuO$_4$ has been under intensive scrutiny over the past years after new NMR measurements unveiled that the superconducting state might be a spin singlet. One of the best order parameter candidates in light of these new experiments is…
We present a microscopic model for the anisotropic exchange interactions in Sr$_{2}$IrO$_{4}$. A direct construction of Wannier functions from first-principles calculations proves the $j_{\mathrm{eff}}$=1/2 character of the spin-orbit…