共查询到10条相似文献,搜索用时 31 毫秒
1.
It is shown that a single impurity can produce a pair of bound states inside the gap of thes-wave van Hove superconductor. Both nonmagnetic and magnetic states have been considered using the Anderson Hamiltonian. The
results are discussed relative to the case of the classical spin in thes-wave van Hove superconductor. 相似文献
2.
Several experimental features in the normal state of cuprates have been interpreted using a pseudogap. We show that these results may be explained by the band structure of the CuO2 planes in the metallic region, which exhibits saddle points (van Hove singularities). 相似文献
3.
I. Grosn 《Journal of Superconductivity and Novel Magnetism》1997,10(3):227-230
The fluctuation contribution to the specific heat of a two-dimensionai superconductor has been calculated, taking into consideration
a logarithmic density of states. The specific heat correction contains a term proportional to (T-T
c)-1 and a logarithmic contribution. It has been shown that this contribution represents a very small correction. The specific
heat correction is analyzed in the critical region where the fluctuations interact strongly. 相似文献
4.
he pair breaking effect in the critical temperature has been considered. We showed that the decrease in the critical temperature
can be described by an Abrikosov-Gorkov-like formula which contains the correction due to the van Hove density of states. 相似文献
5.
S. Ratanaburi P. Udomsamuthirun N. Saentalard S. Yoksan 《Journal of Superconductivity and Novel Magnetism》1997,10(1):1-2
Within the framework of the BCS theory, the gap-to-TC ratioR=2‡
0/kTc is evaluated numerically (‡0 is the energy gap atT = 0 andT>
c is the critical temperature) for a superconductor with a van Hove singularity (vHs) in the density of states as a function
of the shifts (δ) of the Fermi level with respect to the vHs. It is found thatR varies asymmetrically with δ and that the variations are strong near δ = 0. Our numerical calculation shows that the largest
R’s occur at certain values of δ⊋0. 相似文献
6.
The Fermi energy is shown to be pinned near a van Hove singularity for an extended doping range in the one-band and three-band Hubbard models as a consequence of filling dependent band renormalizations. 相似文献
7.
Han Peng Niels B. M. Schröter Jianbo Yin Huan Wang Ting‐Fung Chung Haifeng Yang Sandy Ekahana Zhongkai Liu Juan Jiang Lexian Yang Teng Zhang Cheng Chen Heng Ni Alexey Barinov Yong P. Chen Zhongfan Liu Hailin Peng Yulin Chen 《Advanced materials (Deerfield Beach, Fla.)》2017,29(27)
Graphene has demonstrated great potential in new‐generation electronic applications due to its unique electronic properties such as large carrier Fermi velocity, ultrahigh carrier mobility, and high material stability. Interestingly, the electronic structures can be further engineered in multilayer graphene by the introduction of a twist angle between different layers to create van Hove singularities (vHSs) at adjustable binding energy. In this work, using angle‐resolved photoemission spectroscopy with sub‐micrometer spatial resolution, the band structures and their evolution are systematically studied with twist angle in bilayer and trilayer graphene sheets. A doping effect is directly observed in graphene multilayer system as well as vHSs in bilayer graphene over a wide range of twist angles (from 5° to 31°) with wide tunable energy range over 2 eV. In addition, the formation of multiple vHSs (at different binding energies) is also observed in trilayer graphene. The large tuning range of vHS binding energy in twisted multilayer graphene provides a promising material base for optoelectrical applications with broadband wavelength selectivity from the infrared to the ultraviolet regime, as demonstrated by an example application of wavelength selective photodetector. 相似文献
8.
The critical temperature of a pairing model for HT
c
S has been calculated using an energy-dependent density of states. We showed that the problem which is connected with the van Hove scenario is very sensitive to the energy scale and to the behavior of the density of states at low and high energy. 相似文献
9.
We calculate the conductivity in the ab plane for a superconductor assumed to have a saddle point in the energy surface due to the logarithmic density of states. The influence of the optical phonons was taken into account. At sufficient high temperatures (corresponding to the normal phase) the conductivity is characterized by a Drude-like behavior. 相似文献
10.
B. Krunavakarn P. Udomsamuthirun S. Yoksan I. Grosu M. Crisan 《Journal of Superconductivity》1998,11(2):271-273
We give an analytical expression for the gap-to-T
c ratio (R) of a superconductor with a van Hove singularity in the density of states. Our calculation yields R in very good agreement with the results obtained numerically by S. Ratanaburi et al. [J. Supercond. 9, 485 (1996)]. 相似文献