[en] Multiple Zhang-Rice type spectral features have been observed in resonant inelastic X-ray scattering (RIXS) from the quasi-one-dimensional cuprate charge transfer insulator Li₂CuO₂. The first feature appears at constant emission energy, and is associated with a Zhang-Rice singlet final state. The second is an interplaquette charge transfer excitation that results in a novel triplet Zhang-Rice-type final state. It is accompanied by the presence of a O 2p nonbonding to upper Hubbard band excitation at an energy close to that of a calculated triplet charge transfer Zhang-Rice-type excitation. The site selectivity and polarization rules associated with RIXS allows these two excitations to be distinguished

No abstract available

[en] The apparent contradiction between the recently observed weak charge disproportion and the traditional Mn³⁺/Mn⁴⁺ picture of the charge-orbital orders in half-doped manganites is resolved by a novel Wannier states analysis of the LDA+U electronic structure. Strong electron itinerancy in this charge-transfer system significantly delocalizes the occupied low-energy 'Mn³⁺' Wannier states such that charge leaks into the 'Mn⁴⁺'-sites. Furthermore, the leading mechanisms of the charge order are quantified via our first-principles derivation of the low-energy effective Hamiltonian. The electron-electron interaction is found to play a role as important as the electron-lattice interaction.

[en] We show explicitly how a fixed point can be constructed in scalar $g{\mathrm{\phi <!--\; ??\; -->}}^4$ theory from the solutions to a nonlinear eigenvalue problem. The fixed point is unstable and characterized by $\mathrm{\nu <!--\; ??\; -->}=2/d$ (correlation length exponent), $\mathrm{\eta <!--\; ??\; -->}=1/2-<!--\; ???\; -->d/8$ (anomalous dimension). For d = 2, these exponents reproduce to those of the Ising model which can be understood from the codimension of the critical point. The testable prediction of this fixed point is that the specific heat exponent vanishes. 2d critical Mott systems are well described by this new fixed point. (letter)

[en] We study ideal Bose gas upon two scale-free structures ${\mathcal{G}}^1$ and ${\mathcal{G}}^2$ with identical degree distribution. Energy spectra belonging to tight-binding Hamiltonian are exactly solved and the related spectral dimensions of ${\mathcal{G}}^1$ and ${\mathcal{G}}^2$ are obtained as $d_{s_1}=2$ and $d_{s_2}=2\ln <!--\; ???\; -->4/\ln <!--\; ???\; -->3$. We show that Bose-Einstein condensation only takes place upon ${\mathcal{G}}^2$ instead of ${\mathcal{G}}^1$. The topology and thermodynamical property of the two structures are proven to be totally different. (letter)

[en] The constitutive relations of a dense granular flow composed of self-propelling frictional hard particles are investigated by means of DEM numerical simulations. We show that the rheology, which relates the dynamical friction μ and the volume fraction ϕ to the inertial number I, depends on a dimensionless number $\mathcal{A}$, which compares the active force to the confining pressure. Two liquid/solid transitions —in the Maxwell rigidity sense— are observed. As soon as the activity is turned on, the packing becomes an “active solid” with a mean number of particle contacts larger than the isostatic value. The quasi-static values of μ and ϕ decrease with $\mathcal{A}$. At a finite value of the activity ${\mathcal{A}}_t$, corresponding to the isostatic condition, a second “active rigidity transition” is observed beyond which the quasi-static values of the friction vanishes and the rheology becomes Newtonian. For $\mathcal{A}>{\mathcal{A}}_t$, we provide evidence for a highly intermittent dynamics of this “active fluid”. (letter)

[en] We have carried out a series of helium atom scattering measurements in order to characterise the adsorption properties of hydrogen on antimony(111). Molecular hydrogen does not adsorb at temperatures above 110 K in contrast to pre-dissociated atomic hydrogen. Depending on the substrate temperature, two different adlayer phases of atomic hydrogen on Sb(111) occur. At low substrate temperatures (110 K), the deposited hydrogen layer does not show any ordering while we observe a perfectly ordered $(1\times <!--\; ??\; -->1)$ H/Sb(111) structure for deposition at room temperature. Furthermore, the amorphous hydrogen layer deposited at low temperature forms an ordered overlayer upon heating the crystal to room temperature. Hydrogen starts to desorb at $T_m=430\text{K}$ which corresponds to a desorption energy of $E_{des}=(1.33\pm <!--\; ??\; -->0.06)\text{eV}$. Using measurements of the helium reflectivity during hydrogen exposure at different surface temperatures, we conclude that the initial sticking coefficient of atomic hydrogen on Sb(111) decreases with increasing surface temperature. Furthermore, the scattering cross-section for the diffuse scattering of helium from hydrogen on Sb(111) is determined as $\mathrm{\Sigma <!--\; ??\; -->}=(12\pm <!--\; ??\; -->1){\text{Å<!-- ??? -->}}^2$. (letter)

[en] We propose a scheme to realize rotation sensing through the use of optical lattices with laser-assisted tunneling. We theoretically demonstrate that competition between the rotation and the spin-orbit coupling governs the spin-dependent response of the cyclotron dynamics of the spin-orbit coupled bosons. The Sagnac-type cumulative phase can be read out from the envelope of a beat-frequency time evolution of the population imbalance in the spin-balanced system and enhanced by cyclotron motion. We also theoretically show that the sensitivity limit of the spin-orbit–coupled system to rotational motion can reach $4\times <!--\; ??\; -->{10}^{-<!--\; ???\; -->7}{\text{rads}}^{-<!--\; ???\; -->1}{\text{Hz}}^{-<!--\; ???\; -->1/2}$. (letter)

[en] We perform the possibility to generate a dimer $\mathcal{P}\mathcal{T}$-symmetric model based on a double lambda four-level system in GaAs/AlGaAs quantum wells with biexcitonic transitions. By presenting the detuning management and modulating the Rabi frequencies of the two strong coupling laser fields, we show that the $\mathcal{P}\mathcal{T}$-symmetric model can be realized by the spatial evolution of the weak probe laser and four-wave mixing (FWM)-generated field along the propagation direction. The two weak fields in our model may be used to simulate two laser propagating in two $\mathcal{P}\mathcal{T}$-symmetric parallel waveguides. The diffraction effect also can be studied in some conditions. Our scheme offers two advantages: the complex refractive index is controlled by the strong coupling fields; the symmetry energy exchange between a dimer $\mathcal{P}\mathcal{T}$-symmetric structure is guaranteed by the four-wave mixing process. The present investigation may provide research opportunities in optical experiments. (letter)

[en] The low-formation energy structure of anion interstitial defect in zinc-blende materials is usually identified as the tetrahedron central structure where the anion interstitial atom is surrounded by four countercation atoms. A line-type anion interstitial defect structure $A{D}_i^l$, however, is found to be lower in energy than the tetrahedron central anion interstitial defect structure by first-principles calculations. By analyzing the structural and electronical characters of this line-type defect in relative compounds of zinc-blende materials, we attribute this to the electronegativity shift trends and the bond forming, which lead to the hybridization types varying from sp ³ to sp-like and ending at sp. (letter)