Photo-to-thermal conversion: effective utilization of futile solid-state carbon quantum dots (CQDs) for energy harvesting applications

Dominant non-radiative electronic de-excitation in fluorescence quenched CQDs in the solid state results in excellent photo-to-thermal transduction in the system.</p

Pseudogap and charge ordering in a large-bandwidth electron-doped manganite

We study the origin of complex phase transitions in an electron-doped manganite, La_0.2Sr_0.8MnO₃, using high-resolution photoemission spectroscopy and transmission electron microscopy. The results reveal evidence of phase coexistence and charge ordering in an intermediate temperature range unexpected in this high bandwidth system. The charge ordering nucleates above the phase transition temperature of 265 K, indicating a precursor effect. The high-resolution photoemission spectra exhibit unusual chemical potential shift and persistence of quasiparticles within the insulating phase below 265 K, where the charge-ordered phase dominates and hysteresis is observed in the resistivity. These results provide insight in the study of correlated electron systems exhibiting complex behaviors

Evolution of the electronic structure of HoB_{4} with temperature

We studied the electronic structure of a Shastry-Sutherland lattice system, HoB4 employing high-resolution photoemission spectroscopy and ab initio band-structure calculations. The surface and bulk borons exhibit subtle differences and loss of boron compared to the stoichiometric bulk. However, the surface and bulk conduction bands near Fermi level are found to be similar. Evolution of the electronic structure with temperature is found to be similar to that observed in a typical charge-disordered system. A sharp dip is observed at the Fermi level in the low-temperature spectra revealing a signature of antiferromagnetic gap. Asymmetric spectral weight transfer with temperature manifests particle-hole asymmetry that may be related to the exotic properties of these systems

Evidence of bulk nature of the Kondo effect and different surface potentials in CeB[sub 6]

We have investigated the electronic structure of CeB6 using photoemission spectroscopy as a function of surface sensitivity of the technique. Experimental results provide evidence that Kondo effect is a bulk phenomenon. The Madelung potential at the surface is found to be different from that of the bulk

Surface bulk differences in a conventional superconductor, ZrB12ZrB_{12}

We studied the electronic structure of a conventional superconductor, ZrB12, using high resolutionx-ray photoemission spectroscopy and single crystalline samples. Experimental results withdifferent bulk sensitivity reveal boron deficiency at the surface while the bulk is stoichiometric anddifferent valence states of Zr at the surface relative to those in the bulk. Signature of satellite featuresis observed in the Zr core level spectra corresponding to the bulk of the material suggestingimportance of electron correlation among the conduction electrons in the bulk while the surfaceappears to be uncorrelated. These results provide an insight on surface-bulk differences, which isimportant for fabrication of devices based on such superconductors