共查询到20条相似文献,搜索用时 12 毫秒
1.
Tatnatchai Suwannasit I-Ming Tang Rassmidara Hoonsawat Bumned Soodchomshom 《Journal of Low Temperature Physics》2011,165(1-2):15-26
The Josephson effect in a gapped graphene-based superconductor/barrier/superconductor junction is studied. The superconductivity in gapped graphene may be achieved by depositing conventional superconductor on the top of the gapped graphene such as graphene grown on SiC substrate. In gapped graphene system, the carriers exhibit massive Dirac fermions. We focus on the effect of pseudo-Dirac-like mass on the supercurrent. In contrast to that in the gapless graphene superconductor/barrier/superconductor junction, we find that the supercurrent exhibits dependency of the Fermi energy. Also, the massive supercurrent anomalously oscillates as a function of the gate potential. This novel behavior is due to the effect of electrons acquiring mass in gapped graphene. 相似文献
2.
D. Massarotti B. Jouault V. Rouco G. Campagnano D. Giuliano P. Lucignano D. Stornaiuolo G. P. Pepe F. Lombardi F. Tafuri A. Tagliacozzo 《Journal of Superconductivity and Novel Magnetism》2017,30(1):5-14
Coplanar Al/graphene/Al junctions fabricated on the same graphene sheet deposited on silicon carbide (SiC), show robust Josephson coupling at subKelvin temperature, when the separations between the electrodes is below 400 nm. Remarkably, a hysteretic Critical State sets in when ramping an orthogonal magnetic field, with a sudden collapse of the Josephson critical current I c when turning the field on, and a revival of I c when inverting the sweep. Similar hysteresis can be found in granular superconducting films which may undergo the Berezinskii-Kosterlitz-Thouless transition. Here, we give quantitative arguments to prove that this odd behavior of the magnetoconductance gives evidence for an incipient Berezinskii-Kosterlitz-Thouless transition with drift and pinning of fluctuating free vortices induced by the current bias. 相似文献
3.
M. M. Kaila 《Journal of Superconductivity》2005,18(4):427-431
High temperature Superconductors (HTSCs) are a good candidate for developing THz radiation sensors. They are easy to manufacture
and operate in the convenient temperature range of 80–140 K. The speed of operation of a THz sensor need to be controlled
by a fast dissipation of heat, by the electrons which act as the sensing element. There is recently a surge in the development
of fast and efficient low dimensional thermoelectric, temperature control devices. They would be ideal for cooling of the
sensor, over the temperature interval of operation of the HTSCs. Status of these cooling devices towards achieving low temperature
self cooling is discussed in the paper. Some results of the modeling study, carried out by the author, in an HTSC hot electron
thermal sensor (HETS) are presented. 相似文献
4.
This paper describes a TE013 mode dielectric resonator at 36.098 GHz. The dielectric resonator was formed by sandwiching a cylindrical piece of polished dielectric (sapphire) rod between two GdBa2Cu3O7?x (GBCO) High Temperature Superconductor (HTS) thin films. The resonator was tested as a two-port device at a temperature of 77 K. A 62700 unload quality factor Q 0 was obtained. The surface resistance (Rs) of the HTS film had been determined as 9.4 mΩ at 77 K and 36 GHz. 相似文献
5.
M. M. Kaila 《Journal of Superconductivity and Novel Magnetism》2005,18(4):427-431
High temperature Superconductors (HTSCs) are a good candidate for developing THz radiation sensors. They are easy to manufacture
and operate in the convenient temperature range of 80–140 K. The speed of operation of a THz sensor need to be controlled
by a fast dissipation of heat, by the electrons which act as the sensing element. There is recently a surge in the development
of fast and efficient low dimensional thermoelectric, temperature control devices. They would be ideal for cooling of the
sensor, over the temperature interval of operation of the HTSCs. Status of these cooling devices towards achieving low temperature
self cooling is discussed in the paper. Some results of the modeling study, carried out by the author, in an HTSC hot electron
thermal sensor (HETS) are presented. 相似文献
6.
Bi-2212超导材料是最具高场应用前景的超导材料之一.经过近20年的研究,多芯Bi-2212超导线(带)材的临界电流密度(Jc)和临界工程电流密度(JE)已达到工程应用要求,并已在国外实现了产业化生产.综述了近年来Bi-2212超导材料在成材技术、载流性能、应用方面的研究进展,分析了该类材料成材技术中的关键问题,并探讨了进一步提高Bi-2212超导材料实用性能的途径. 相似文献
7.
The field dependence of real () and imaginary () component of ac susceptibility of superconductors within the critical state model can conveniently be used for evaluating the critical current when field amplitude is larger than the penetration field. A method to analyze the real () and imaginary () component of fundamental ac susceptibility with the objective of extracting the temperature dependence of critical current density J
c(T) is reported. The procedure makes use of the ac susceptibility data of two polycrystalline (Bi-Pb)-2223 samples measured with different excitation amplitudes below and close to the critical temperature. The temperature dependence of J
c is extracted using the isothermal scan over and data. Results obtained from this procedure are found to be in fair agreement with J
c(T) calculated from traditional loss-maximum data. 相似文献
8.
Anomalous and Highly Efficient InAs Nanowire Phototransistors Based on Majority Carrier Transport at Room Temperature 下载免费PDF全文
Nan Guo Weida Hu Lei Liao SenPo Yip Johnny C. Ho Jinshui Miao Zhi Zhang Jin Zou Tao Jiang Shiwei Wu Xiaoshuang Chen Wei Lu 《Advanced materials (Deerfield Beach, Fla.)》2014,26(48):8203-8209
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M. Piat J. P. Torre J. W. Beeman J. M. Lamarre R. S. Bhatia 《Journal of Low Temperature Physics》2001,125(5-6):189-203
We have modelled low temperature semiconducting thermometers by using a semi-analytical approach of Anderson insulators, taking into account both the electrical field and the electron/phonon decoupling effects. We first used this simulation to fit measured V(I) curves to validate this method and to obtain physical parameters of NTD Ge and NbSi thin film samples around 100mK. We show that considering the two effects separately leads to an overestimate of each one. Once validated, our algorithm was used to optimise the design of high sensitivity thermometers for the High Frequency Instrument (HFI) of the Planck satellite. 相似文献
11.
James C. Booth Kenneth Leong Susan A. Schima C. Collado J. M. O’Callaghan J. Mateu 《Journal of Superconductivity and Novel Magnetism》2006,19(7-8):531-540
We experimentally demonstrate the equivalence of different manifestations of nonlinear response in high temperature superconductor (HTS) microwave devices. Using a combination of analytical and numerical analysis, we show that the results of intermodulation distortion measurements, harmonic generation measurements, and power-dependent resonator measurements of different coplanar waveguide structures patterned onto the same HTS thin-film sample all yield approximately the same values for the nonlinear penetration depth. The extraction of an underlying nonlinear material parameter that is independent of the specific device geometry and experimental configuration will allow our results to be quantitatively compared with other nonlinear measurements, and will therefore help in determining the dominant source(s) of nonlinear response in HTS microwave devices. 相似文献
12.
Teet ?rd Küllike R?go Artjom Vargunin 《Journal of Superconductivity and Novel Magnetism》2012,25(5):1351-1356
We study the peculiarities of coherency in a two-gap superconductor. Both intraband couplings, inducing superconductivity in the independent bands, and interband pair-transfer interaction have been taken into account. On the basis of the Ginzburg?CLandau equations derived from the Bogoliubov?Cde Gennes equations and the relevant self-consistency conditions for a two-gap system, we find critical and non-critical coherence lengths in the spatial behaviour of the fluctuations of order parameters. The character of the temperature dependencies of these length scales is determined by the relative contributions from intra- and interband interaction channels. 相似文献
13.
This paper describes a TE013 mode dielectric resonator at 36.098 GHz. The dielectric resonator was formed by sandwiching a cylindrical piece of polished dielectric (sapphire) rod between two GdBa2Cu3O7–x (GBCO) High Temperature Superconductor (HTS) thin films. The resonator was tested as a two-port device at a temperature of 77 K. A 62700 unload quality factor Q
0 was obtained. The surface resistance (Rs) of the HTS film had been determined as 9.4 m at 77 K and 36 GHz. 相似文献
14.
Karlis Bormanis Marite Kalnberga Maris Livinsh Aloizijs Patmalnieks Andris Sternberg 《Journal of Low Temperature Physics》1999,117(3-4):807-811
Layers of superconductor YBa
2
Cu
3
O
7–
materials synthesized from oxides have been sedimented on ceramics and single crystal substrates and fired in accordance with melt textured growth (MTG) technology. Results of microscopic studies of surfaces of the layers are reported. The effect of substrate material on the structure formation of the layers is discussed. 相似文献
15.
A simple model of electrical resistivity for some copper oxides, in the normal state, and at low temperatures, is given. We show that the logarithmic temperature dependence can be obtained taking into consideration a non–Fermi-liquid model with a singular density of states and in the presence of randomly distributed nonmagnetic impurities, without taking into consideration the localization effects. 相似文献
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17.
利用Mg扩散法制备出单相多晶的MgB2 超导体 ,其超导转变的零电阻温度为 3 8 4K左右 ,转变宽度小于 1K。正常态电阻率温度关系为金属型 ,在 2 70K -4 5 0K的高温范围内电阻率与温度成很好的线性关系。差热和热重分析表明在空气气氛中MgB2 在 90 0℃左右开始急剧氧化。 相似文献
18.
We present measurements of the power-dependent microwave surface impedance of YBa2Cu3O7– thin films, performed using patterned coplanar waveguide (CPW) resonators at 5.87 GHz and 76 K. We compare these resonator measurements with third-harmonic generation measurements performed on CPW transmission lines of the same geometry patterned onto the same thin-film sample at the same frequency and temperature. We find that the power-dependent surface reactance Xs(Prf) is directly related to the magnitude of the generated third-harmonic signal, indicating a common origin for both of these manifestations of nonlinearity in high temperature superconductor (HTS) devices. These results are consistent with the nonlinear response generated by a current-dependent penetration depth (J), which provides a material limitation on the linearity that can be achieved in any practical HTS microwave device. 相似文献
19.
H. Courtois Sukumar Rajauria P. Gandit F. W. J. Hekking B. Pannetier 《Journal of Low Temperature Physics》2008,153(5-6):325-338
We discuss inherent thermometry in a Superconductor-Normal metal-Superconductor tunnel junction. In this configuration, the energy selectivity of single-particle tunneling can provide a significant electron cooling, depending on the bias voltage. The usual approach for measuring the electron temperature consists in using an additional pair of superconducting tunnel junctions as probes. In this paper, we discuss our experiment performed on a different design with no such thermometer. The quasi-equilibrium in the central metallic island is discussed in terms of a kinetic equation including injection and relaxation terms. We determine the electron temperature by comparing the micro-cooler experimental current-voltage characteristic with isothermal theoretical predictions. The limits of validity of this approach, due to the junctions asymmetry, the Andreev reflection or the presence of sub-gap states are discussed. 相似文献
20.
B. Krunavakarn S. Kaskamalas S. Yoksan 《Journal of Superconductivity and Novel Magnetism》2004,17(2):297-301
On the basis of Fermi liquid theory, we study the thermodynamic properties near zero temperature of a d-wave superconductor assuming the BCS pairing model. The temperature dependence of the order parameter is derived. We then obtain an analytical expression for the free energy difference between the normal and superconducting states in the vicinity of zero temperature from the coupling constant integral. New expressions for the critical field and the specific heat in the superconducting state are given as functions of temperature. We compare our expressions with previous formulas due to others. 相似文献