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111.
We have observed the Fano-Kondo antiresonance in a quantum wire with a side-coupled quantum dot. In a weak coupling regime, dips due to the Fano effect appeared. As the coupling strength increased, conductance in the regions between the dips decreased alternately. From the temperature dependence and the response to the magnetic field, we conclude that the conductance reduction is due to the Fano-Kondo antiresonance. At a Kondo valley with the Fano parameter q approximately 0, the phase shift is locked to pi/2 against the gate voltage when the system is close to the unitary limit in agreement with theoretical predictions by Gerland et al. [Phys. Rev. Lett. 84, 3710 (2000)]. 相似文献
112.
Fujikawa Y Nagao T Yamada-Takamura Y Sakurai T Hashimoto T Morikawa Y Terakura K Lagally MG 《Physical review letters》2005,94(8):086105
The structure and stability of the hydrogen-terminated (105) surface of Ge deposited on Si(105) substrates are investigated by scanning tunneling microscopy (STM). Investigations combining STM, electron energy loss spectroscopy, and theory reveal that Si incorporation into the surface Ge layer of hydrogen-terminated Ge/Si(105) drastically destabilizes the surface. The STM images obtained on this surface are well explained by the recently established rebonded-step structure model. 相似文献
113.
Thayer GE Sadowski JT Meyer zu Heringdorf F Sakurai T Tromp RM 《Physical review letters》2005,95(25):256106
We show that the orientation of pentacene molecules is controlled by the electronic structure of the surface on which they are deposited. We suggest that the near-Fermi level density of states above the surface controls the interaction of the substrate with the pentacene pi orbitals. A reduction of this density as compared to noble metals, realized in semimetallic Bi(001) and Si(111)(5 x 2)Au surfaces, results in pentacene standing up. Interestingly, pentacene grown on Bi(001) is highly ordered, yielding the first vertically oriented epitaxial pentacene thin films observed to date. 相似文献
114.
It is reported that optical selection rules still apply in light emission from the scanning tunneling microscope (STM). Linear polarization of isochromat light emitted from the tunneling gap between a STM tip made of tungsten (W) and a silicon (Si) sample with a (001) clean surface strongly depends on the bias voltage between tip and sample. The results show that pi* and sigma* surface states, for example, of the Si(001) sample contribute to emission of p- and s-polarized light, respectively, in accordance with optical selection rules. 相似文献
115.
Observation of "partial coherence" in an Aharonov-Bohm interferometer with a quantum dot 总被引:1,自引:0,他引:1
We report experiments on the interference through spin states of electrons in a quantum dot (QD) embedded in an Aharonov-Bohm (AB) interferometer. We have picked up a spin-pair state, for which the environmental conditions are ideally similar. The AB amplitude is traced in a range of gate voltage that covers the pair. The behavior of the asymmetry in the amplitude around the two Coulomb peaks agrees with the theoretical prediction that the spin-flip process in a QD is related to the quantum dephasing of electrons. These results constitute evidence of "partial coherence" due to an entanglement of spins in the QD and in the interferometer. 相似文献
116.
Luminescence channels of manganese-doped spinel 总被引:1,自引:0,他引:1
Ayana Tomita Kensuke Tanaka Masanobu Shirai Kouichirou Tanaka Eiichi Hanamura 《Journal of luminescence》2004,109(1):19-24
Two independent luminescence channels are observed from manganese-doped spinel Mn:MgAl2O4. The luminescence around 520 nm is assigned to transition from the lowest electronic excited state 4T1 to the ground state 6A1 of Mn2+ (3d)5 ion by analyzing the excitation spectrum and electron spin resonance measurement. The emission at 650 nm is triggered by the band edge excitation and is assigned similarly to the charge-transfer process associated with the manganese ion. 相似文献
117.
Taniguchi T Yamanaka K Sumioka H Yamazaki T Tabata Y Kawarazaki S 《Physical review letters》2004,93(24):246605
The extraordinary Hall resistivity rho(xy) and the magnetization M of a canonical spin glass AuFe (8 at.% Fe) were measured simultaneously as functions of temperature with the best care to the thermal and the magnetic field hysteresis. The data of rho(xy) show an anomaly at the spin glass transition temperature T(g) and have different zero field cooling (ZFC) and field cooling (FC) measurements below T(g). Moreover, the value of rho(xy)/M, which represents the chiral susceptibility of the system in the present case, also shows the difference between ZFC and FC measurements. The results are consistent with the predictions of the chirality scenario of canonical spin glasses by Kawamura. 相似文献
118.
The irradiation of N-(4-substituted benzoyl)-α-dehydroarylalanine alkyl esters (1) in methanol containing triethylamine (TEA) was found to quantitatively give cis- and trans-4,5-dihydrooxazole derivatives (2), which were described as being formed via electron transfer from TEA to the excited-state (E)-1 followed by kinetically-controlled cyclization of the (E)-1-derived anion radical. A product composition analysis showed that the cis-2/trans-2 composition ratio is greatly varied depending on the stereoelectronic properties of the substituents, the polarity of protic solvents and the concentration of TEA. 相似文献
119.
Takafuji M Ishiodori A Yamada T Sakurai T Ihara H 《Chemical communications (Cambridge, England)》2004,(9):1122-1123
Enhanced CD spectra based on chirally-oriented structures of pyrene-containing L-glutamic acid-derived lipid were observed in polymerizable monomers and CD strength was maintained after photo-induced polymerization of the monomer solvents. 相似文献
120.
We study theoretically the effect of deformed microelliptical cavities on lasing characteristics. We show that the transition of stationary lasing states from unidirectional rotational waves to a mixture of clockwise and anticlockwise rotational waves occurs when the shape of a disk is deformed to that of an ellipse. 相似文献