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A Four-Phase Improvement of Grover's Algorithm
Bo-Wen Ma, Wan-Su Bao, Tan Li, Feng-Guang Li, Shuo Zhang, Xiang-Qun Fu
Chin. Phys. Lett. 2017, 34 (7):
070305
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DOI: 10.1088/0256-307X/34/7/070305
When applying Grover's algorithm to an unordered database, the probability of obtaining correct results usually decreases as the quantity of target increases. A four-phase improvement of Grover's algorithm is proposed to fix the deficiency, and the unitary and the phase-matching condition are also proposed. With this improved scheme, when the proportion of target is over 1/3, the probability of obtaining correct results is greater than 97.82% with only one iteration using two phases. When the computational complexity is $O(\sqrt{M/N})$, the algorithm can succeed with a probability no less than 99.63%.
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Accretion onto the Magnetically Charged Regular Black Hole
M. Azam, A. Aslam
Chin. Phys. Lett. 2017, 34 (7):
070401
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DOI: 10.1088/0256-307X/34/7/070401
We investigate the accretion process for static spherically symmetric geometry, i.e., magnetically charged regular black hole with isotropic fluid. We obtain generalized expressions for the velocity ($u(r)$), speed of sound ($c^2_{\rm s}$), energy density ($\rho(r)$) and accretion rate ($\dot{M}$) at the critical point near the regular black hole during the accretion process. We also plot these physical parameters against fixed values of charge, mass and different values of equation of state parameter to study the process of accretion. We find that radial velocity and energy density of the fluid remain positive and negative as well as rate of change of mass is increased and decreased for dust, stiff, quintessence fluid and phantom-like fluid, respectively.
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A High-Sensitivity Terahertz Detector Based on a Low-Barrier Schottky Diode
Xiao-Yu Liu, Yong Zhang, De-Jiao Xia, Tian-Hao Ren, Jing-Tao Zhou, Dong Guo, Zhi Jin
Chin. Phys. Lett. 2017, 34 (7):
070701
.
DOI: 10.1088/0256-307X/34/7/070701
A low-barrier Schottky barrier diode based on the InGaAs/InP material system is designed and fabricated with a new non-destructive dry over-etching process. By using this diode, a high-sensitivity waveguide detector is proposed. The measured maximum responsivity is over 2000 mV/mW at 630 GHz. The measured noise effective power (NEP) is less than 35 pW/Hz$^{0.5}$ at 570–630 GHz. The minimum NEP is 14 pW/Hz$^{0.5}$ at 630 GHz. The proposed high-sensitivity waveguide detector has the characteristics of simple structure, compact size, low cost and high performance, and can be used in a variety of applications such as imaging, molecular spectroscopy and atmospheric remote sensing.
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Constructions and Preliminary HV Conditioning of a Photocathode Direct-Current Electron Gun at IHEP
Xiao-Ping Li, Jiu-Qing Wang, Jin-Qiang Xu, Shi-Lun Pei, Ou-Zheng Xiao, Da-Yong He, Kun Lv, Xiang-Cheng Kong, Xiao-Hua Peng
Chin. Phys. Lett. 2017, 34 (7):
072901
.
DOI: 10.1088/0256-307X/34/7/072901
As one of the most important key technologies for future advanced light source based on the energy recovery linac, a photocathode dc electron gun is supported by Institute of High Energy Physics (IHEP) to address the technical challenges of producing very low emittance beams at high average current. Construction of the dc gun is completed and a preliminary high voltage conditioning is carried out up to 440 kV. The design, construction and preliminary HV conditioning results for the dc gun are described.
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Intracavity Spontaneous Parametric Down-Conversion in Bragg Reflection Waveguide Edge Emitting Diode
Si-Hang Wei, Xiang-Jun Shang, Ben Ma, Ze-Sheng Chen, Yong-Ping Liao, Hai-Qiao Ni, Zhi-Chuan Niu
Chin. Phys. Lett. 2017, 34 (7):
074202
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DOI: 10.1088/0256-307X/34/7/074202
A four-wavelength Bragg reflection waveguide edge emitting diode based on intracavity spontaneous parametric down-conversion and four-wave mixing (FWM) processes is made. The structure and its tuning characteristic are designed by the aid of FDTD mode solution. The laser structure is grown by molecular beam epitaxy and processed to laser diode through the semiconductor manufacturing technology. Fourier transform infrared spectroscopy is applied to record wavelength information. Pump around 1.071 μm, signal around 1.77 μm, idler around 2.71 μm and FWM signal around 1.35 μm are observed at an injection current of 560 mA. The influences of temperature, carrier density and pump wavelength on tuning characteristic are shown numerically and experimentally.
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Frequency Stabilization of a Microsecond Pulse Sodium Guide Star Laser with a Tilt- and Temperature-Tuned Etalon
Chang Xu, Jun-Wei Zuo, Qi Bian, Chuan Guo, Yong Bo, Lu Feng, Kai Jin, Kai Wei, Hong-Wei Gao, Sheng Zhang, Yuan-Qin Xia, Qin-Jun Peng, Zu-Yan Xu
Chin. Phys. Lett. 2017, 34 (7):
074203
.
DOI: 10.1088/0256-307X/34/7/074203
A frequency stabilization approach is introduced for the microsecond pulse sodium beacon laser using an intra-cavity tilt- and temperature-tuned etalon based on a computer-controlled feedback system connected with a fast high-precision wavelength meter. The frequency stability of the sodium beacon lasers is compared with and without feedback loop controlling. The output wavelength of the laser is locked to the sodium D$_{2a}$ absorption line (589.159 nm) over 12 h with the feedback loop controlling technology. As a result, the sodium laser guide star is successfully observed by the telescope of National Astronomical Observatories at Xinglong. This approach can also be used for other pulses and continuous-wave lasers for the frequency stabilization.
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High-Efficiency Generation of 0.12mJ, 8.6Fs Pulses at 400nm Based on Spectral Broadening in Solid Thin Plates
Yang-Yang Liu, Kun Zhao, Peng He, Hang-Dong Huang, Hao Teng, Zhi-Yi Wei
Chin. Phys. Lett. 2017, 34 (7):
074204
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DOI: 10.1088/0256-307X/34/7/074204
We demonstrate efficient generation of continuous spectrum centered at 400 nm from solid thin plates. By frequency doubling of 0.8 mJ, 30 fs Ti:sapphire laser pulses with a BBO crystal, 0.2 mJ, 33 fs laser pulses at 400 nm are generated. Focusing the 400-nm pulses into 7 thin fused silica plates, we obtain 0.15 mJ continuous spectrum covering 350–450 nm. After compressing by 3 pairs of chirped mirrors, 0.12 mJ, 8.6 fs pulses are achieved. To the best of our knowledge, this is the first time that sub-10-fs pulses centered at 400 nm are generated by solid thin plates, which shows that spectral broadening in solid-state materials works not only at 800 nm but also at different wavelengths.
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Effect of Phase Modulation on Electromagnetically Induced Grating in a Five-Level M-Type Atomic System
Li Wang, Yi-Hong Qi, Li Deng , Yue-Ping Niu, Shang-Qing Gong, Hong-Ju Guo
Chin. Phys. Lett. 2017, 34 (7):
074206
.
DOI: 10.1088/0256-307X/34/7/074206
We theoretically investigate the phenomena of electromagnetically induced grating in an M-type five-level atomic system. It is found that a weak field can be effectively diffracted into high-order directions using a standing wave coupling field, and different depths of the phase modulation can disperse the diffraction light into different orders. When the phase modulation depth is approximated to the orders of $\pi$, $2\pi$ and $3\pi$, the first-, second- and third-order diffraction intensity reach the maximum, respectively. Thus we can take advantage of the phase modulation to control the probe light dispersing into the required high orders.
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Tight Focusing Properties of Azimuthally Polarized Pair of Vortex Beams through a Dielectric Interface
C. A. P. Janet, M. Lavanya, K. B. Rajesh, M. Udhayakumar, Z. Jaroszewicz, D. Velauthapillai
Chin. Phys. Lett. 2017, 34 (7):
074209
.
DOI: 10.1088/0256-307X/34/7/074209
Tight focusing properties of an azimuthally polarized Gaussian beam with a pair of vortices through a dielectric interface is theoretically investigated by vector diffraction theory. For the incident beam with a pair of vortices of opposite topological charges, the vortices move toward each other, annihilate and revive in the vicinity of focal plane, which results in the generation of many novel focal patterns. The usable focal structures generated through the tight focusing of the double-vortex beams may find applications in micro-particle trapping, manipulation, and material processing, etc.
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A 420nm Blue Diode Laser for the Potential Rubidium Optical Frequency Standard
Sheng-Nan Zhang, Xiao-Gang Zhang, Jian-Hui Tu, Zhao-Jie Jiang, Hao-Sen Shang, Chuan-Wen Zhu, Wei Yang, Jing-Zhong Cui, Jing-Biao Chen
Chin. Phys. Lett. 2017, 34 (7):
074211
.
DOI: 10.1088/0256-307X/34/7/074211
We report a 420 nm external cavity diode laser with an interference filter (IF) of 0.5 nm narrow-bandwidth and 79% high transmission, which is first used for Rb optical frequency standard. The IF and the cat-eye reflector are used for selecting wavelength and light feedback, respectively. The measured laser linewidth is 24 kHz when the diode laser is free running. Using this narrow-linewidth IF blue diode laser, we realize a compact Rb optical frequency standard without a complicated PDH system. The preliminary stability of the Rb optical frequency standard is $2\times10^{-13}$ at 1 s and decreases to $1.9\times10^{-14}$ at 1000 s. The narrow-linewidth characteristic makes the IF blue diode laser a well suited candidate for the compact Rb optical frequency standard.
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Source Range Estimation Based on Pulse Waveform Matching in a Slope Environment
Zu-Yong Wu, Ren-He Zhang, Ji-Xing Qin, Zhao-Hui Peng, Zhou Meng
Chin. Phys. Lett. 2017, 34 (7):
074301
.
DOI: 10.1088/0256-307X/34/7/074301
An approach of source range estimation in an ocean environment with sloping bottom is presented. The approach is based on pulse waveform correlation matching between the received and simulated signals. An acoustic propagation experiment is carried out in a slope environment. The pulse signal is received by the vertical line array, and the depth structure can be obtained. For the experimental data, the depth structures of pulse waveforms are different, which depends on the source range. For a source with unknown range, the depth structure of pulse waveform can be first obtained from the experimental data. Next, the depth structures of pulse waveforms in different ranges are numerically calculated. After the process of correlating the experimental and simulated signals, the range corresponding to the maximum value of the correlation coefficient is the estimated source range. For the explosive sources in the experiment with two depths, the mean relative errors of range estimation are both less than 7%.
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Simulation of Double-Front Detonation of Suspended Mixed Cyclotrimethylenetrinitramine and Aluminum Dust in Air
Wen-Tao Zan, He-Fei Dong, Tao Hong
Chin. Phys. Lett. 2017, 34 (7):
074701
.
DOI: 10.1088/0256-307X/34/7/074701
The two-phase detonation of suspended mixed cyclotrimethylenetrinitramine (i.e., RDX) and aluminum dust in air is simulated with a two-phase flow model. The parameters of the mixed RDX-Al dust detonation wave are obtained. The double-front detonation and steady state of detonation wave of the mixed dust are analyzed. For the dust mixed RDX with density of 0.565 kg/m$^{3}$ and radius of 10 μm as well as aluminum with density of 0.145 kg/m$^{3}$ and radius of 4 μm, the detonation wave will reach a steady state at 23 m. The effects of the size of aluminum on the detonation are analyzed. For constant radius of RDX particles with radius of 10 μm, as the radius of aluminum particles is larger than 2.0 μm, the double-front detonation can be observed due to the different ignition distances and reaction rates of RDX and aluminum particles. As the radius of aluminum particles is larger, the velocity, pressure and temperature of detonation wave will be slower. The pressure at the Chapman–Jouguet (CJ) point also becomes lower. Comparing the detonation with single RDX dust, the pressure and temperature in the flow field of detonation of mixed dust are higher.
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LaB$_{6}$ Work Function and Structural Stability under High Pressure
Peng-Shan Li, Wei-Ran Cui, Rui Li, Hua-Lei Sun, Yan-Chun Li, Dong-Liang Yang, Yu Gong, Hui Li, Xiao-Dong Li
Chin. Phys. Lett. 2017, 34 (7):
076201
.
DOI: 10.1088/0256-307X/34/7/076201
The work functions of the (110) and (100) surfaces of LaB$_{6}$ are determined from ambient pressure to 39.1 GPa. The work function of the (110) surface slowly decreases but that of the (100) surface remains at a relatively constant value. To determine the reason for this difference, the electron density distribution (EDD) is determined from high-pressure single-crystal x-ray diffraction data by the maximum entropy method. The EDD results show that the chemical bond properties in LaB$_{6}$ play a key role. The structural stability of LaB$_{6}$ under high pressure is also investigated by single-crystal x-ray diffraction. In this study, no structural or electronic phase transition is observed from ambient pressure to 39.1 GPa.
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Coupled Two-Dimensional Atomic Oscillation in an Anharmonic Trap
Dong Hu, Lin-Xiao Niu, Jia-Hua Zhang, Xin-Hao Zou, Shu-Yang Cao, Xiao-Ji Zhou
Chin. Phys. Lett. 2017, 34 (7):
076701
.
DOI: 10.1088/0256-307X/34/7/076701
In atomic dynamics, oscillation along different axes can be studied separately in the harmonic trap. When the trap is not harmonic, motion in different directions may couple together. In this work, we observe a two-dimensional oscillation by exciting atoms in one direction, where the atoms are transferred to an anharmonic region. Theoretical calculations are coincident to the experimental results. These oscillations in two dimensions not only can be used to measure trap parameters but also have potential applications in atomic interferometry and precise measurements.
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Analytic Continuation with Padé Decomposition
Xing-Jie Han, Hai-Jun Liao, Hai-Dong Xie, Rui-Zhen Huang, Zi-Yang Meng, Tao Xiang
Chin. Phys. Lett. 2017, 34 (7):
077102
.
DOI: 10.1088/0256-307X/34/7/077102
The ill-posed analytic continuation problem for Green's functions or self-energies can be carried out using the Padé rational polynomial approximation. However, to extract accurate results from this approximation, high precision input data of the Matsubara Green function are needed. The calculation of the Matsubara Green function generally involves a Matsubara frequency summation, which cannot be evaluated analytically. Numerical summation is requisite but it converges slowly with the increase of the Matsubara frequency. Here we show that this slow convergence problem can be significantly improved by utilizing the Padé decomposition approach to replace the Matsubara frequency summation by a Padé frequency summation, and high precision input data can be obtained to successfully perform the Padé analytic continuation.
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BiPh-$m$-BiDPO as a Hole-Blocking Layer for Organic Light-Emitting Diodes: Revealing Molecular Structure-Properties Relationship
Ning-Ning Chen, Wan-Yi Tan, Dong-Yu Gao, Jian-Hua Zou, Jun-Zhe Liu, Jun-Biao Peng, Yong Cao, Xu-Hui Zhu
Chin. Phys. Lett. 2017, 34 (7):
077203
.
DOI: 10.1088/0256-307X/34/7/077203
We report a simple hole-blocking material (biphenyl-3,3'-diyl)bis(diphenylphosphine oxide) (BiPh-$m$-BiDPO) based on our recent advance. The bis(phosphine oxide) compound shows HOMO/LUMO levels of $\sim$$-6.71/-2.51$ eV. Its phosphorescent spectrum in a solid film features two major emission bands peaking at 2.69 and 2.4 eV, corresponding to 0–0 and 0–1 vibronic transitions, respectively. The measurement of the electron-only devices reveals that BiPh-$m$-BiDPO possesses electron mobility of $2.28\times10^{-9}$–$3.22\times10^{-8}$ cm$^{2}$V$^{-1}$s$^{-1}$ at $E=2$–$5\times10^{5}$ V/cm. The characterization of the sky blue fluorescent and red phosphorescent pin organic light-emitting diodes (OLEDs) utilizing BiPh-$m$-BiDPO as the hole blocker shows that its shallow LUMO level as well as the low electron mobility affects significantly the power efficiency and hence operational stability, relative to the luminous efficiency, especially at high luminance. In combination with our recent results, the present study provides an indepth insight on the molecular structure-property correlation in the organic phosphinyl-containing hole-blocking materials.
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The Efficiency Droop of InGaN-Based Green LEDs with Different Superlattice Growth Temperatures on Si Substrates via Temperature-Dependent Electroluminescence
Wei-Jing Qi, Long-Quan Xu, Chun-Lan Mo, Xiao-Lan Wang, Jie Ding, Guang-Xu Wang, Shuan Pan, Jian-Li Zhang, Xiao-Ming Wu, Jun-Lin Liu, Feng-Yi Jiang
Chin. Phys. Lett. 2017, 34 (7):
077301
.
DOI: 10.1088/0256-307X/34/7/077301
InGaN-based green light-emitting diodes (LEDs) with different growth temperatures of superlattice grown on Si (111) substrates are investigated by temperature-dependent electroluminescence between 100 K and 350 K. It is observed that with the decrease of the growth temperature of the superlattice from 895$^{\circ}\!$C to 855$^{\circ}\!$C, the forward voltage decreases, especially at low temperature. We presume that this is due to the existence of the larger average size of V-shaped pits, which is determined by secondary ion mass spectrometer measurements. Meanwhile, the sample with higher growth temperature of superlattice shows a severer efficiency droop at cryogenic temperatures (about 100 K–150 K). Electron overflow into p-GaN is considered to be the cause of such phenomena, which is relevant to the poorer hole injection into multiple quantum wells and the more reduced effective active volume in the active region.
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Revisiting the Electron-Doped SmFeAsO: Enhanced Superconductivity up to 58.6K by Th and F Codoping
Xiao-Chuan Wang, Jia Yu, Bin-Bin Ruan, Bo-Jin Pan, Qing-Ge Mu, Tong Liu, Kang Zhao, Gen-Fu Chen, Zhi-An Ren
Chin. Phys. Lett. 2017, 34 (7):
077401
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DOI: 10.1088/0256-307X/34/7/077401
In the iron-based high-$T_{\rm c}$ bulk superconductors, $T_{\rm c}$ above 50 K was only observed in the electron-doped 1111-type compounds. Here we revisit the electron-doped SmFeAsO polycrystals to make a further investigation for the highest $T_{\rm c}$ in these materials. To introduce more electron carriers and less crystal lattice distortions, we study the Th and F codoping effects into the Sm-O layers with heavy electron doping. Dozens of Sm$_{1-x}$Th$_{x}$FeAsO$_{1-y}$F$_{y}$ samples are synthesized through the solid state reaction method, and these samples are carefully characterized by the structural, resistive, and magnetic measurements. We find that the codoping of Th and F clearly enhances the superconducting $T_{\rm c}$ more than the Th or F single-doped samples, with the highest record $T_{\rm c}$ up to 58.6 K when $x=0.2$ and $y=0.225$. Further element doping causes more impurities and lattice distortions in the samples with a weakened superconductivity.
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In Situ Electronic Structure Study of Epitaxial Niobium Thin Films by Angle-Resolved Photoemission Spectroscopy
Pai Xiang, Ji-Shan Liu, Ming-Ying Li, Hai-Feng Yang, Zheng-Tai Liu, Cong-Cong Fan, Da-Wei Shen , Zhen Wang, Zhi Liu
Chin. Phys. Lett. 2017, 34 (7):
077402
.
DOI: 10.1088/0256-307X/34/7/077402
High-quality single crystalline niobium films are grown on a-plane sapphire in molecular beam epitaxy. The film is single crystalline with a (110) orientation, and both the rocking curve and the reflection high-energy electron diffraction pattern demonstrate its high-quality with an atomically smooth surface. By in situ study of its electronic structure, a rather weak electron-electron correlation effect is demonstrated experimentally in this $4d$ transition metal. Moreover, a kink structure is observed in the electronic structure, which may result from electron-phonon interaction and it might contribute to the superconductivity. Our results help to understand the properties of niobium deeply.
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Superconducting (Li,Fe)OHFeSe Film of High Quality and High Critical Parameters
Yulong Huang, Zhongpei Feng, Shunli Ni, Jun Li, Wei Hu, Shaobo Liu, Yiyuan Mao, Huaxue Zhou, Fang Zhou, Kui Jin, Huabing Wang, Jie Yuan, Xiaoli Dong, Zhongxian Zhao
Chin. Phys. Lett. 2017, 34 (7):
077404
.
DOI: 10.1088/0256-307X/34/7/077404
A superconducting film of (Li$_{1-x}$Fe$_{x})$OHFeSe is reported for the first time. The thin film exhibits a small in-plane crystal mosaic of 0.22$^{\circ}$, in terms of the full width at half maximum of the x-ray rocking curve, and an excellent out-of-plane orientation by x-ray $\varphi $-scan. Its bulk superconducting transition temperature $T_{\rm c}$ of 42.4 K is characterized by both zero electrical resistance and diamagnetization measurements. The upper critical field $H_{\rm c2}$ is estimated to be 79.5 T and 443 T for the magnetic field perpendicular and parallel to the $ab$ plane, respectively. Moreover, a large critical current density $J_{\rm c}$ of a value over 0.5 MA/cm$^{2}$ is achieved at $\sim $20 K. Such a (Li$_{1-x}$Fe$_{x})$OHFeSe film is therefore not only important to the fundamental research for understanding the high-$T_{\rm c}$ mechanism, but also promising in the field of high-$T_{\rm c}$ superconductivity application, especially in high-performance electronic devices and large scientific facilities such as superconducting accelerator.
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Gapped Spin-1/2 Spinon Excitations in a New Kagome Quantum Spin Liquid Compound Cu$_3$Zn(OH)$_6$FBr
Zili Feng, Zheng Li, Xin Meng, Wei Yi, Yuan Wei, Jun Zhang, Yan-Cheng Wang, Wei Jiang, Zheng Liu, Shiyan Li, Feng Liu, Jianlin Luo, Shiliang Li, Guo-qing Zheng, Zi Yang Meng, Jia-Wei Mei, Youguo Shi
Chin. Phys. Lett. 2017, 34 (7):
077502
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DOI: 10.1088/0256-307X/34/7/077502
We report a new kagome quantum spin liquid candidate Cu$_3$Zn(OH)$_6$FBr, which does not experience any phase transition down to 50 mK, more than three orders lower than the antiferromagnetic Curie-Weiss temperature ($\sim$200 K). A clear gap opening at low temperature is observed in the uniform spin susceptibility obtained from $^{19}$F nuclear magnetic resonance measurements. We observe the characteristic magnetic field dependence of the gap as expected for fractionalized spin-1/2 spinon excitations. Our experimental results provide firm evidence for spin fractionalization in a topologically ordered spin system, resembling charge fractionalization in the fractional quantum Hall state.
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Dependence of Nonlinear Optical Response of Anatase TiO$_{2}$ on Shape and Excitation Intensity
Lu-Hua Guo, Ying-Wei Wang, Yong-Qiang Jiang, Si Xiao, Jun He
Chin. Phys. Lett. 2017, 34 (7):
077803
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DOI: 10.1088/0256-307X/34/7/077803
Nonlinear optical (NLO) properties of anatase TiO$_{2}$ with nanostructures of nanoparticle (NP), nanowire (NW) and annealed nanowire (NWA) are studied by open-aperture and closed-aperture $Z$-scan techniques with a femtosecond pulsed laser at wavelengths of 532 nm and 780 nm simultaneously. At 532 nm, when increasing excitation intensity, NLO absorption of TiO$_{2}$ NPs transforms from saturable absorption to reverse-saturable absorption. However, NWs and NWAs exhibit the opposite change. At 780 nm, all samples show reverse-saturable absorption, but have different sensitivities to excitation intensity. Due to the larger surface-to-volume ratio of NPs and less defects of NWAs by annealing, nonlinear optical absorption coefficients follow the order NPs$\ge$NWs$\ge$NWAs. The results also show that these shape and annealing effects are dominant at low excitation intensity, but do not exhibit at the high excitation intensity. The NLO refractive index of NPs shows a positive linear relationship with the excitation intensity, whereas NW and NWAs exhibit a negative linear relationship. The results could provide some foundational guidance to applications of anatase TiO$_{2}$ in optoelectronic devices or other aspects.
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Experimental $I$–$V$ and $C$–$V$ Analysis of Schottky-Barrier Metal-Oxide-Semiconductor Field Effect Transistors with Epitaxial NiSi$_{2}$ Contacts and Dopant Segregation
Yi-Ze Wang, Chang Liu, Jian-Hui Cai, Qiang Liu, Xin-Ke Liu, Wen-Jie Yu, Qing-Tai Zhao
Chin. Phys. Lett. 2017, 34 (7):
078501
.
DOI: 10.1088/0256-307X/34/7/078501
We present an experimental analysis of Schottky-barrier metal-oxide-semiconductor field effect transistors (SB-MOSFETs) fabricated on ultrathin body silicon-on-insulator substrates with a steep junction by the dopant implantation into the silicide process. The subthreshold swing of such SB-MOSFETs reaches 69 mV/dec. Emphasis is placed on the capacitance-voltage analysis of p-type SB-MOSFETs. According to the measurements of gate-to-source capacitance $C_{\rm gs}$ with respect to $V_{\rm gs}$ at various $V_{\rm ds}$, we find that a maximum occurs at the accumulation regime due to the most imbalanced charge distribution along the channel. At each $C_{\rm gs}$ peak, the difference between $V_{\rm gs}$ and $V_{\rm ds}$ is equal to the Schottky barrier height (SBH) for NiSi$_{2}$ on highly doped silicon, which indicates that the critical condition of channel pinching off is related with SBH for source/drain on channel. The SBH for NiSi$_{2}$ on highly doped silicon can affect the pinch-off voltage and the saturation current of SB-MOSFETs.
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67 articles
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