Signature of hidden order and evidence for periodicity modification in URu₂Si₂

The detail of electronic structures near the Fermi level in URu2Si2 has been investigated employing state-of-art laser angle-resolved photoemission spectroscopy. The observation of a narrow dispersive band near the Fermi level in the ordered state as well as its absence in a Rh-substituted sample strongly suggest that the emergence of the narrow band is a clear signature of the hidden-order transition. The temperature dependence of the narrow band, which appears at the onset of the hidden-order transition, invokes the occurrence of periodicity modification in the ordered state, which is shown for the first time by any spectroscopic probe. We compare our data to other previous studies and discuss possible implications

Electronic Structure of the Novel Filled Skutterudite PrPt₄Ge₁₂ Superconductor

We have performed soft x-ray photoemission spectroscopy (SXPES) and resonant photoemission spectroscopy (RPES) of the filled skutterudite superconductor PrPt4Ge12 in order to study the electronic structure of valence band and the character of Pr 4f. SXPES of PrPt4Ge12 measured with 1200 eV photon energy, where spectral contribution of Pr 4f is negligible, was found nearly identical with that of LaPt4Ge12, indicating similarity of Pt–Ge derived electronic states of the two compounds. Good correspondence with band calculations allows us to ascribe the dominant Ge 4p character of the density of states at the Fermi level (EF). Pr 3d → 4f RPES shows that, although Pr 4f electrons in PrPt4Ge12 are not as strongly hybridized with conduction electrons near EF as in PrFe4P12, there are finite Pr 4f contribution to the states near EF in PrPt4Ge12. These PES results give the information of fundamental electronic structure for understanding the physical properties of the novel filled skutterudite superconductor PrPt4Ge12

Multiple phosphorus chemical sites in heavily phosphorus-doped diamond

We have performed high-resolution core level photoemission spectroscopy on a heavily phosphorus (P)-doped diamond film in order to elucidate the chemical sites of doped-phosphorus atoms in diamond. P 2p core level study shows two bulk components, providing spectroscopic evidence for multiple chemical sites of doped-phosphorus atoms. This indicates that only a part of doped-phosphorus atoms contribute to the formation of carriers. From a comparison with band calculations, possible origins for the chemical sites are discussed

Ultrahigh-resolution laser photoemission study of URu₂Si₂ across the hidden-order transition

We have studied the electronic structures of URu2Si2 employing ultrahigh-resolutionlaser angle-resolved photoemission spectroscopy. The change of photoemission spectra is investigated across the hidden-ordertransition, and the emergence of a narrow band is clearly observed near the Fermi level for both (π,0) and (π,π) directions. In addition, it is shown that tuning of light's polarization allows the signal of a hole-like dispersive feature to enhance. These observations prove that laser angle-resolved photoemission spectroscopy is an effective tool for studying the evolution of electronic structures across the hidden-ordertransition in URu2Si2

Comparative photoemission studies on the superconducting gap of the filled skutterudite superconductors LaPt₄Ge₁₂ and PrPt₄Ge₁₂

We performed a comparative study of the superconducting gap in the new filled skutterudite superconductors LaPt4Ge12 and PrPt4Ge12 using high-resolution photoemission spectroscopy. We succeeded in observing spectral changes across Tc that reflect the opening of the superconducting gap in both compounds and also in observing a noticeable difference in their respective superconducting spectral shapes near the Fermi level, pointing toward a more complex superconducting gap structure in PrPt4Ge12. In addition, we found that the two-gap model is more suitable for describing the superconducting-state spectrum of PrPt4Ge12 than the single-isotropic-gap and single-anisotropic-gap models, which suggests an explanation that multiband effects may possibly induce the anomalous superconducting properties of PrPt4Ge12

Photoemission study of Ca-intercalated graphite superconductor CaC₆

In this work, we have performed resonant photoemission studies of Ca-intercalated graphite superconductor CaC6. Using photon energy of the Ca 2p-3d threshold, the photoemission intensity of the peak at Fermi energy (E-F) is resonantly enhanced. This result provides spectroscopic evidence for the existence of Ca 3d states at E-F, and strongly supports that Ca 3d state plays a crucial role for the superconductivity of this material with relatively high T-c

Dose-finding and efficacy confirmation trial of superselective intra-arterial infusion of cisplatin and concomitant radiotherapy for patients with locally advanced maxillary sinus cancer (JCOG1212, RADPLAT-MSC)

A dose-finding and efficacy confirmation trial was started in Japan in April 2014 to evaluate the efficacy and safety of superselective intra-arterial infusion of cisplatin and concomitant radiotherapy for locally advanced maxillary sinus cancer. A total of 18 patients will be enrolled in the dose-finding phase for the determination of the recommended number of cisplatin cycles, and 65 patients with T4aN0M0 and 62 patients with T4bN0M0, including those who received the recommended number of or fewer cycles in the dose-finding phase, will be enrolled from 16 institutions within a 5-year period in the efficacy confirmation phase. The primary endpoints of the dose-finding and the efficacy confirmation phases are dose-limiting toxicities and 3-year overall survival, respectively. This trial was registered at the UMIN Clinical Trials Registry (http://www.umin.ac.jp/ctr/) under Trial No. UMIN000013706