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11.
For the first time, the optical absorption edge of the magnetic semiconductor europium telluride has been studied at low temperature (1.7 K) as a function of magnetic field in the high field range 0 ≤ H ≤ 9.5 Tesla, and related to the magnetic phase diagram of this material. The exponential absorption edge has been parameterized using a magnetic field dependent extension of Urbach's rule, and the observations are found to be consistent with a simple dependence of the gap parameter on polarization and magnetic field. 相似文献
12.
The pressure dependence of the band gap of tellurium has been precisely measured to 8 kbar in a study of the laser emission of an optically-pumped sample at liquid nitrogen temperatures. A large negative pressure tuning coefficient is observed along with an anomalous nonlinearity in the tuning. These measurements are compared to previous studies using other optical and electrical techniques and are related to current theoretical models of the band structure of tellurium. 相似文献
13.
Results on the temperature variation from 2 ? T ? 300 K of the c-axis electrical resistivity and thermopower of a donor stage-5 potassium and an acceptor stage-2 FeCl3 graphite intercalation compounds are reported. Comparing the data with those of the literature reveals for both compounds a different qualitative behavior for low and high stages. 相似文献
14.
The wavevector distribution excited by light scattering in opaque materials is calculated and compared to recently observed asymmetrical Brillouin lineshapes. 相似文献
15.
J. Boxus B. Poulaert J-P. Issi H. Mazurek M.S. Dresselhaus 《Solid State Communications》1981,38(12):1117-1119
The low-temperature variation of the in-plane thermal conductivity of graphite- FeCl3 intercalation compounds is reported. Around room temperature, though holes are participating, there is an important lattice contribution, but much smaller than in pristine graphite. The electronic contribution dominates in the liquid helium range. These preliminary results suggest lattice thermal conductivity measurements as a new tool to investigate defects introduced by intercalation. 相似文献
16.
Ultraviolet photoemission spectroscopy in ultrahigh vacuum has been used to study the interaction of H2O with argon-ion-bombarded and annealed TiO2(110) and SrTiO3 (100) surfaces. At low exposure, evidence is found for the presence of the OH free radical on both bombarded and annealed TiO2. At high exposure, a spectrum of slightly perturbed adsorbed H2O is observed, with the a1 molecular orbital shifted 0.5–1 eV toward tighter binding. This suggests that H2O binds to the surface of TiO2 via its a1, in-plane O lone-pair orbital. No evidence is found for OH on the surface of SrTiO3. The spectrum of H2O adsorbed on bombarded SrTiO3 shows both the a1 and b2 molecular orbitals shifted 0.4 toward tighter binding, indicating a more complicated bonding to the surface. For SrTiO3 that has been bombarded and then annealed, the spectrum of adsorbed H2O shows no significant bonding effects. 相似文献
17.
Chan Kim Takemasa Fujino Yoshiyuki Nishimura Toshio Tamaki Morinobu Endo Mildred S. Dresselhaus 《Molecular Crystals and Liquid Crystals》2013,570(1):505-510
Abstract The microstructure of milled mesophase pitch-based carbon fibers (mMPCFs) that have been developed as an anode material for Li ion batteries have been studied as a function of heat treatment temperature (HTT), by SEM, X-ray diffraction, and Raman spectroscopy. And the results obtained are compared with those by X-ray diffraction (XRD) and SEM observations, for the characterization of specific structural features of mMPCFs as a promising anode material. 相似文献
18.
The magnetic susceptibility, conductivity, magnetoresistance (MR) and Hall effect of copper-doped carbon aerogels are measured and compared with corresponding results from the original carbon aerogels. The experimental results indicate that the temperature-dependent magnetic susceptibility of the copper-doped and of the original carbon aerogels is well fit by a Curie function at low temperatures. The copper-doped carbon aerogels show a higher susceptibility and spin concentration than the original carbon aerogel. After doping by copper, the materials exhibit a more linear current-voltage curve than the original carbon aerogel under the same measurement conditions. The electrical resistance of the copper-doped carbon aerogels is strikingly lower than that of the original carbon aerogels, and decreases with increasing copper content in the samples. The temperature-dependent resistivity ρ(T) of all of the copper-doped and original carbon aerogels can be fitted by an exp(T−1/2) dependence for T<100 K. The copper-doped and pristine carbon aerogels follow a quadratic MR behavior Δρ/ρ=AB2 in the magnetic field range B investigated (up to 5 T), except at very low temperatures (T<4 K). 相似文献
19.
Yong Chae Jung Hiroyuki Muramatsu Ki Chul Park Daisuke Shimamoto Jin Hee Kim Takuya Hayashi Sung Moo Song Yoong Ahm Kim Morinobu Endo Mildred S. Dresselhaus 《Macromolecular rapid communications》2009,30(24):2084-2088
It is demonstrated that an optically transparent and electrically conductive polyethylene oxide (PEO) film is fabricated by the introduction of individualized single‐walled carbon nanotubes (SWNTs). The incorporated SWNTs in the PEO film sustain their intrinsic electronic and optical properties and, in addition, the intrinsic properties of the polymer matrix are retained. The individualized SWNTs with smaller diameter provide high transmittance as well as good electrical conductivity in PEO films.
20.
Souza Filho AG Kobayashi N Jiang J Grüneis A Saito R Cronin SB Mendes Filho J Samsonidze GG Dresselhaus G Dresselhaus MS 《Physical review letters》2005,95(21):217403
In this Letter, we report the effects of strain on the electronic properties of single-wall carbon nanotubes. When we normalize the electronic transition energies to the corresponding values obtained for unstrained tubes, we obtain that, regardless of the tube diameter, all the data collapse onto universal curves following an n - m = constant family pattern. In the case of metallic tubes, quantum interference effects on the Raman cross section are predicted for strained tubes when the energies of the lower and the upper components have nearly the same values. Experimental evidence for the strain-induced Raman cross section changes is observed in single nanotube spectroscopy. 相似文献