Xiunian Jing
Chinese Academy of Sciences
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Featured researches published by Xiunian Jing.
Scientific Reports | 2012
Fanming Qu; Fan Yang; Jie Shen; Yue Ding; Jun Chen; Zhongqing Ji; Guangtong Liu; Jie Fan; Xiunian Jing; Changli Yang; Li Lu
To study the interface between a conventional superconductor and a topological insulator, we fabricated Pb-Bi2Te3-Pb lateral and sandwiched junctions, and performed electron transport measurements down to low temperatures. The results show that there is a strong superconducting proximity effect between Bi2Te3 and Pb, as that a supercurrent can be established along the thickness direction of the Bi2Te3 flakes (100~300 nm thick) at a temperature very close to the superconducting Tc of Pb. Moreover, a Josephson current can be established over several microns in the lateral direction between two Pb electrodes on the Bi2Te3 surface. We have further demonstrated that superconducting quantum interference devices can be constructed based on the proximity-effect-induced superconductivity. The critical current of the devices exhibits s-wave-like interference and Fraunhofer diffraction patterns. With improved designs, Josephson devices of this type would provide a test-bed for exploring novel phenomena such as Majorana fermions in the future.
Physical Review Letters | 2011
H. Yu; Xiaobo Zhu; Z. H. Peng; Ye Tian; D. J. Cui; G H Chen; D. N. Zheng; Xiunian Jing; Li Lu; S. P. Zhao; Siyuan Han
Quantum phase diffusion in a small underdamped Nb/AlO(x)/Nb junction (∼0.4 μm(2)) is demonstrated in a wide temperature range of 25-140 mK where macroscopic quantum tunneling (MQT) is the dominant escape mechanism. We propose a two-step transition model to describe the switching process in which the escape rate out of the potential well and the transition rate from phase diffusion to the running state are considered. The transition rate extracted from the experimental switching current distribution follows the predicted Arrhenius law in the thermal regime but is greatly enhanced when MQT becomes dominant.
Review of Scientific Instruments | 2012
Ye Tian; H. Yu; Hui Deng; G. M. Xue; D. T. Liu; Y. Ren; G H Chen; D. N. Zheng; Xiunian Jing; Li Lu; S. P. Zhao; Siyuan Han
We develop a small-signal measurement system on cryogen-free dilution refrigerator which is suitable for superconducting qubit studies. Cryogen-free refrigerators have several advantages such as less manpower for system operation and large sample space for experiment, but concern remains about whether the noise introduced by the coldhead can be made sufficiently low. In this work, we demonstrate some effective approaches of acoustic isolation to reduce the noise impact. The electronic circuit that includes the current, voltage, and microwave lines for qubit coherent state measurement is described. For the current and voltage lines designed to have a low pass of dc-100 kHz, we show that the measurements of Josephson junctions switching current distribution with a width down to 1 nA, and quantum coherent Rabi oscillation and Ramsey interference of the superconducting qubit can be successfully performed.
Physical Review B | 2010
H. Yu; Xiyu Zhu; Z. H. Peng; Wenhuan Cao; D. J. Cui; Ye Tian; G H Chen; D. N. Zheng; Xiunian Jing; Li Lu; S. P. Zhao; Siyuan Han
The properties of phase escape in a dc superconducting quantum interference device (SQUID) at 25 mK, which is well below quantum-to-classical crossover temperature T(cr), in the presence of strong resonant ac driving have been investigated. The SQUID contains two Nb/Al-AlO(x)/Nb tunnel junctions with Josephson inductance much larger than the loop inductance so it can be viewed as a single junction having adjustable critical current. We find that with increasing microwave power W and at certain frequencies nu and nu/2, the single primary peak in the switching current distribution, which is the result of macroscopic quantum tunneling of the phase across the junction, first shifts toward lower bias current I and then a resonant peak develops. These results are explained by quantum resonant phase escape involving single and two photons with microwave-suppressed potential barrier. As W further increases, the primary peak gradually disappears and the resonant peak grows into a single one while shifting further to lower I. At certain W, a second resonant peak appears, which can locate at very low I depending on the value of nu. Analysis based on the classical equation of motion shows that such resonant peak can arise from the resonant escape of the phase particle with extremely large oscillation amplitude resulting from bifurcation of the nonlinear system. Our experimental result and theoretical analysis demonstrate that at T << T(cr), escape of the phase particle could be dominated by classical process, such as dynamical bifurcation of nonlinear systems under strong ac driving.
Physical Review B | 2005
G. T. Liu; J. L. Luo; N. L. Wang; Xiunian Jing; Duo Jin; Tao Xiang; Zh Wu
A series of compounds M0.1Sr0.9Cu2(BO3)(2) with Sr substituted by M=Al, La, Na, and Y and YxSr1-xCu2(BO3)(2) with x=0.06, 0.08, 0.10, 0.20, and 0.30 were prepared by solid state reaction. X-ray diffraction analysis showed that these doping compounds are isostructural to SrCu2(BO3)(2). The resistivity at room temperature, the magnetic susceptibility from 1.9 to 300 K in an applied magnetic field of 1.0 T and the specific heat from 1.9 to 25 K in applied fields up to 14 T were measured, respectively. The spin gap is deduced from the low temperature susceptibility as well as the specific heat. It is found that the spin gap is strongly suppressed by magnetic fields and the doping content. No superconductivity is observed in all doping samples.
Chinese Physics B | 2016
Yuan Pang; Junhua Wang; Zhaozheng Lyu; Guang Yang; Jie Fan; Guangtong Liu; Zhongqing Ji; Xiunian Jing; Changli Yang; Li Lu
On the road of searching for Majorana fermions in condensed matter systems, a highly-sought signature is full gap-closing, as a condition for hosting the Majorana zero modes, in Josephson devices constructed on the surface of topological insulators. In this Letter, we present direct experimental evidence of gap-closing in single Josephson junctions constructed on Bi
Physical Review B | 2017
Junhua Wang; Xinxin Gong; Guang Yang; Zhaozheng Lyu; Yuan Pang; Guangtong Liu; Zhongqing Ji; Jie Fan; Xiunian Jing; Changli Yang; Fanming Qu; Xiaofeng Jin; Li Lu
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New Journal of Physics | 2013
H. Yu; Xiyu Zhu; J K Ren; Z. H. Peng; D. J. Cui; Hui Deng; Wenhuan Cao; Ye Tian; G H Chen; D. N. Zheng; Xiunian Jing; Li Lu; S. P. Zhao
Te
Chinese Physics B | 2018
Zhi Gang Cheng; Jie Fan; Xiunian Jing; Li Lu
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Chinese Physics Letters | 2017
Guang-Tong Liu; Y. L. Zhu; Qin Wang; Yuan Pang; Jie Fan; Xiunian Jing; Zhong-Qing Ji; Changli Yang; Li Lu; Rui-Rui Du; Loren Pfeiffer; K. W. West
surface via local contact-resistance measurement.