Ferromagnetism and the Kondo effect are crucial for 3d electrons to become spin-separated and heavy at the same time.

No abstract

We have systematically studied the behaviors of the resistivity and magnetization of CeSb 2 single crystals as a function of temperature and external field. Four anomalies in the resistivity/magnetization-versus-temperature curves are observed at low magnetic field. They are located at 15.5 K, 11.5 K, 9.5 K, and 6.5 K, corresponding to the paramagnetic-magnetically ordered state (MO), MO-antiferromagnetic (AFM), AFM-AFM, and AFM-ferromagnetic (FM) transitions, respectively. The anomaly at 9.5 K is only visible with H [010] by magnetic susceptibility measurements, indicating that the AFM-AFM transition only happens along [010] direction in ab-plane. The four magnetic transitions are strongly suppressed by high external field. Finally, the field-temperature phase diagrams of CeSb 2 with different orientations of the applied field in ab-plane are constructed and indicate the highly anisotropic nature of the magnetization of CeSb 2 .

Hidden order in URu 2 Si 2 has remained a mystery now entering its 4th decade. The importance of resolving the nature of the hidden order has stimulated extensive research. Here we present a detailed characterization of different surface terminations in URu 2 Si 2 by angle-resolved photoemission spectroscopy, in conjunction with scanning tunneling spectroscopy and DMFT calculations that may unveil a new piece of this puzzle. The Uterminated surface is characterized by an electron-like band around theX point, while a hole-like band for the Si-terminated surface. We also investigate temperature evolution of the electronic structure around theX point from 11 K up to 70 K, and did not observe any abrupt change of the electronic structure around the coherence temperature (55 K). The f spectral weight gradually weakens upon increasing temperature, still some f spectral weight can be found above this temperature. Our results suggest that surface terminations in URu 2 Si 2 are an important issue to be taken into account in future work. Phys. Rev. Lett. 55, 755 (1985).

The band structure, intra-and interband scattering processes of the electrons at the surface of a bismuth-bilayer on Bi2Se3 have been experimentally investigated by low-temperature Fouriertransform scanning tunneling spectroscopy. The observed complex quasiparticle interference patterns are compared to a simulation based on the spin-dependent joint density of states approach using the surface-localized spectral function calculated from first principles as the only input. Thereby, the origin of the quasiparticle interferences can be traced back to intraband scattering in the bismuth bilayer valence band and Bi2Se3 conduction band, and to interband scattering between the two-dimensional topological state and the bismuth-bilayer valence band. The investigation reveals that the bilayer band gap, which is predicted to host one-dimensional topological states at the edges of the bilayer, is pushed several hundred milli-electronvolts above the Fermi level. This result is rationalized by an electron transfer from the bilayer to Bi2Se3 which also leads to a two-dimensional electron state in the Bi2Se3 conduction band with a strong Rashba spin-splitting, coexisting with the topological state and bilayer valence band.