Momentum-Dependent Hybridization Gap and dispersive in-gap state of The Kondo Semiconductor SmB6

We report the temperature-dependent three-dimensional angle-resolved photoemission spectra of the Kondo semiconductor SmB$_6$. We found a difference in the temperature dependence of the peaks at the X and $\Gamma$ points, due to hybridization between the Sm 5d conduction band and the nearly localized Sm 4f state. The peak intensity at the X point has the same temperature dependence as the valence transition below 120 K, while that at the $\Gamma$ point is consistent with the magnetic excitation at Q=(0.5,0.5,0.5) below 30 K. This suggests that the hybridization with the valence transition mainly occurs at the X point, and the initial state of the magnetic excitation is located at the $\Gamma$ point.Comment: 5 pages, 3 figure

Temperature and Frequency Dependences of Line Width of Antiferromagnetic Resonance in Europium Telluride(Physics)

EuTe is a second kind f. c. c. antiferromagnet. The line width of the antiferromagnetic resonance of the single crystal has been measured at frequencies of 9.20, 22.12, and 33.99 GHz in the temperature range between 1.25 and 4.20 K. The measurements have been performed on the spin-flop mode with the resonance field applied in the easy plane (111). The results show that the temperature dependence of the line width strongly depends on the used frequency. The line width at 9.20 GHz increases with temperature as exp (-5/T), the one at 22.12 GHz increases linearly with T, and at 33.99 GHz it increases very slowly with T. The essential behavior of the temperature and frequency dependences is theoretically explained in terms of the three-magnon process derived from the exchange interaction

Development of an epileptic seizure prediction algorithm using R–R intervals with self-attentive autoencoder

Epilepsy is a neurological disorder that may affect the autonomic nervous system (ANS) from 15 to 20 min before seizure onset, and disturbances of ANS affect R–R intervals (RRI) on an electrocardiogram (ECG). This study aims to develop a machine learning algorithm for predicting focal epileptic seizures by monitoring R–R interval (RRI) data in real time. The developed algorithm adopts a self-attentive autoencoder (SA-AE), which is a neural network for time-series data. The results of applying the developed seizure prediction algorithm to clinical data demonstrated that it functioned well in most patients; however, false positives (FPs) occurred in specific participants. In a future work, we will investigate the causes of FPs and optimize the developing seizure prediction algorithm to further improve performance using newly added clinical data

Anomalous pressure effect on the Nèel temperature and volume of DyB6

The pressure effect on the Nèel temperature TN of DyB6 has been investigated by measuring the temperature dependence of electrical resistivity (ρ) at various pressures up to 8 GPa. It was found that TN increases almost linearly with pressure in the range of 0-2 GPa and then tends to saturate above 2 GPa. The pressure derivative of TN below 2 GPa was estimated to be 2.6 K/GPa. The pressure effect on the volume of DyB6 has also been measured at high pressure up to 14 GPa at room temperature using X-ray diffraction and diamond anvil cell. The pressure dependence of volume of LaB6 was also measured for the comparison. It is revealed that DyB6 is more compressible than LaB6. The origin for this observation is suggested to be due to the difference of the ionic size of the rare earth elements, or the strong electron-phonon interaction in DyB6

Exchange-displacement waves in GdB6

15 pagesInternational audienc

Raman scattering investigation of RB6 (R=Ca, La, Ce, Pr, Sm, Gd, Dy, and Yb)

The excitation-energy, polarization, and temperature dependeces of Raman scattering spectra have been measured for the RB6 crystals (R=Ca 2+, La3+, Ce3+, Pr3+, Sm 2.6+, Gd3+, Dy3+, and Yb2+). In the divalent crystals of CaB6 and YbB6, the Eg phonon shows doublet, while the line shape is a broad single peak for the trivalent case. In the trivalent crystals, two kinds of the extra peaks have been clearly observed at around 200 cm-1 and at around 1400 cm -1 in addition to the Raman-active phonons and crystal electric-field (CEF) excitations. The peak intensities at around 200 cm -1 show the anomalous decrease with decreasing temperature, and this temperature dependence correlates with that of the mean-square displacement of the R ion. Furthermore, their energies decrease with the increase of the cage space due to B6. These peaks are originated from the second-order excitation of acoustic phonons. The broad peak at around 1400 cm-1 is assigned as the second-order excitation of the T2g phonon. For the T2g phonon, the energy difference and its line-shape change between the trivalent and divalent crystals suggests the existence of electron-phonon interaction. We have observed the CEF excitation in PrB 6 and have obtained the Lea, Leask, and Wolf parameters with x=0.94 and W=9.2 K

Journal of Electron Spectroscopy and Related Phenomena 101--103 (1999) 761--764

Reflectivity spectra of rare-earth borides (RB ; R5rare-earth, x54, 6, 12) in the VUV energy range and boron 1s x absorption spectra of YB , YB and LuB were systematically measured in order to investigate the role of the B-cluster in 46 12 x the optical spectra and the physical properties. In the optical spectra, the bonding states of B - and B-cluster are dominant 612 in RB (x54, 6) and RB , respectively. The electronic structures of the B - and the B-cluster are discussed. 1999 x 12 6 12 Elsevier Science B.V. All rights reserved

Surface electronic structure of the NdB6(110) clean surface studied by angle-resolved photoemission spectroscopy

An angle-resolved photoemission study of the NdB6(110) clean surface has been done in order to investigate in detail the surface electronic structure. From the dependence of the valence-band photoemission spectra on the surface condition and the exciting photon energy, we found additional peaks corresponding to the surface states on the NdB6(110) surface. These surface states are located at around 1.8 eV in binding energy. The dispersion relations of these surface states were determined along the Γ + ̄-M̄ symmetry line in the surface Brillouin zone and it is found that the energy dispersion for the present surface state is about 250 meV. From the photon energy dependence and the analogy of these observations with previous results for the LaB6(110) clean surface, it is concluded that the present surface states have the same specifications as those of the LaB6(110) surface and are ascribed to the B 2p dangling bonds of the surface B framework