Electronic structures of UTSn (T=Ni, Pd) using photoemission spectroscopy

We study the electronic structure of an exotic superconductor, PdTe employing depth-resolved high resolution photoemission spectroscopy and density functional theory. The valence band spectra exhibit large density of states at the Fermi level with flat intensity in a wide energy range indicating highly metallic ground state. The Pd 4d-Te 5p hybridization is found to be strong leading to a highly covalent character of the itinerant states. Core level spectra exhibit several fe...

The layered transition metal chalcogenides have been a fertile land in solid state physics for many decades. Various MX2-type transition metal dichalcogenides, such as WTe2, IrTe2, and MoS2, have triggered great attention recently, either for the discovery of novel phenomena or some extreme or exotic physical properties, or for their potential applications. PdTe2 is a superconductor in the class of transition metal dichalcogenides, and superconductivity is enhanced in its Cu-...

We have revisited the valence band electronic structure of NiO by means of hard x-ray photoemission spectroscopy (HAXPES) together with theoretical calculations using both the GW method and the local density approximation + dynamical mean-field theory (LDA+DMFT) approaches. The effective impurity problem in DMFT is solved through the exact diagonalization (ED) method. We show that the LDA+DMFT method alone cannot explain all the observed structures in the HAXPES spectra. GW c...

Bulk-sensitive high-resolution photoemission was carried out on a prototype 3d1 metallic Sr1-xCaxVO3. In a strong contrast to so far reported results, the bulk spectral functions are revealed to be insensitive to x. The conservation of the density of states at the Fermi level in spite of the electron correlation is clarified by the successful suppression and deconvolution of the surface contribution. Our study has demonstrated the importance of high-energy and high-resolution...

The valence state of UTe$_2$ was studied by core-level photoelectron spectroscopy. The main peak position of the U $4f$ core-level spectrum of UTe$_2$ coincides with that of UB$_2$, which is an itinerant compound with a nearly $5f^3$ configuration. However, the main peak of UTe$_2$ is broader than that of UB$_2$, and satellite structures are observed in the higher binding energy side of the main peak, which are characteristics of mixed-valence uranium compounds. These results...

Resonant photoemission (RPES) at the Ce 3d -> 4f threshold has been performed for alpha-like compound CeNi_2 with extremely high energy resolution (full width at half maximum < 0.2 eV) to obtain bulk-sensitive 4f spectral weight. The on-resonance spectrum shows a sharp resolution-limited peak near the Fermi energy which can be assigned to the tail of the Kondo resonance. However, the spin-orbit side band around 0.3 eV binding energy corresponding to the f_{7/2} peak is washed...

We have studied the electronic structure of Mo rich Mo$_{1-x}$Re$_x$ alloys (0$\leq$ x $\leq$0.4) using valence band photoemission spectroscopy in the photon energy range 23-70 eV and density of states calculations. Comparison of the photoemission spectra with the density of states calculations suggests that with respect to the Fermi level $E_F$, the $d$ states lie mostly in the range 0 to -6 eV binding energy whereas $s$ states lie in the range -4 to -10 eV binding energy. W...

The electronic structure of the antiferromagnet uranium nitride (UN) has been studied by angle resolved photoelectron spectroscopy using soft X-rays (hn=420-520 eV). Strongly dispersive bands with large contributions from the U 5f states were observed in ARPES spectra, and form Fermi surfaces. The band structure as well as the Fermi surfaces in the paramagnetic phase are well explained by the band-structure calculation treating all the U 5f electrons as being itinerant, sugge...

Actinide elements produce a plethora of interesting physical behaviors due to the 5f states. This review compiles and analyzes progress in understanding of the electronic and magnetic structure of the 5f states in actinide metals. Particular interest is given to electron energy-loss spectroscopy and many-electron atomic spectral calculations, since there is now an appreciable library of core d -> valence f transitions for Th, U, Np, Pu, Am, and Cm. These results are interwove...

We have measured Ce 4f spectral weights of extremely $\alpha$-like Ce-transition metal intermetallic compounds CeRh$_x$ (x=2,3) and CeNi$_x$ (x=2,5) by using the {\it bulk-sensitive} resonant photoemission technique at the Ce $M_5$($3d_{5/2}\to4f$)-edge. Unprecedentedly high energy resolution and longer escape depth of photoemitted electron at this photon energy enabled us to distinguish the sharp Kondo resonance tails at the Fermi level, which can be well described by the Gu...