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1.
This paper studies the properties of a kind of portable ultra-bright
microfocus x-ray source with the Monte-Carlo method in detail. The new
x-ray source consists of an electron-emission system, an
electrostatic focusing system and a metal target. A crystal
Lanthanum Hexaboride cathode, a Wehnelt grid and an extracted
electrode compose the triode electrode electron-gun system. Two
equal radius cylinder electrodes form the focusing system. The key
factors determining the focus properties of the electron beam such as the
ratio Dw/H, grid bias Vg, and the properties of the
extracted electrode are numerically studied. The calculated results
reveal that when Dw/H, Vg, the length of
the extracted electrode, and the distance between the grid and the extracted
electrode equals 5, --0.6~kV, 10~mm, and 8~mm respectively, the
electron beam focal spot can be concentrated down to 9~μm in
radius and a reasonable focal length about 72.5~mm can be achieved,
at the same time, the cathode emission currents can be as high as
30~mA. 相似文献
2.
Influence of reducing anneal on the ferromagnetism in single crystalline Co-doped ZnO thin films 下载免费PDF全文
This paper reports that the high-quality Co-doped ZnO
single crystalline films have been grown on $a$-plane sapphire
substrates by using molecular-beam epitaxy. The as-grown films show
high resistivity and non-ferromagnetism at room temperature, while
they become good conductive and ferromagnetic after annealing in the
reducing atmosphere either in the presence or absence of Zn vapour.
The x-ray absorption studies indicate that all Co ions in these
samples actually substituted into the ZnO lattice without formatting
any detectable secondary phase. Compared with weak ferromagnetism
(0.16~$\mu _{\rm B}$/Co$^{2 + })$ in the Zn6110M, 7550P, 7280E, 7870D http://cpb.iphy.ac.cn/CN/10.1088/1674-1056/19/5/056101 https://cpb.iphy.ac.cn/CN/article/downloadArticleFile.do?attachType=PDF&id=111756 Co-doped ZnO, diluted magnetic semiconductors, x-ray
absorption fine structure, single crystalline thin films Project partially supported by
National Science Foundation of China (Grant No.~10804017), National
Science Foundation of Jiangsu Province of China (Grant
No.~BK2007118), Research Fund for the Doctoral Program of Higher
Education of China (Grant No.~20070286037), Cyanine-Project
Foundation of Jiangsu Province of China (Grant No.~1107020060),
Foundation for Climax Talents Plan in Six-Big Fields of Jiangsu
Province of China (Grant No.~1107020070) and New Century Excellent
Talents in University (NCET-05-0452). This paper reports that the high-quality Co-doped ZnO
single crystalline films have been grown on $a$-plane sapphire
substrates by using molecular-beam epitaxy. The as-grown films show
high resistivity and non-ferromagnetism at room temperature, while
they become good conductive and ferromagnetic after annealing in the
reducing atmosphere either in the presence or absence of Zn vapour.
The x-ray absorption studies indicate that all Co ions in these
samples actually substituted into the ZnO lattice without formatting
any detectable secondary phase. Compared with weak ferromagnetism
(0.16~$\mu _{\rm B}$/Co$^{2 + })$ in the Zn$_{0.95}$Co$_{0.05}$O
single crystalline film with reducing annealing in the absence of Zn
vapour, the films annealed in the reducing atmosphere with Zn vapour
are found to have much stronger ferromagnetism (0.65~$\mu _{\rm
B}$/Co$^{2 + })$ at room temperature. This experimental studies
clearly indicate that Zn interstitials are more effective than
oxygen vacancies to activate the high-temperature ferromagnetism in
Co-doped ZnO films, and the corresponding ferromagnetic mechanism is
discussed. Co-doped;ZnO;diluted;magnetic;semiconductors;x-ray;absorption;fine;structure;single;crystalline;thin;films This paper reports that the high-quality Co-doped ZnO single crystalline films have been grown on a-plane sapphire substrates by using molecular-beam epitaxy.The as-grown films show high resistivity and non-ferromagnetism at room temperature,while they become more conductive and ferromagnetic after annealing in the reducing atmosphere either in the presence or absence of Zn vapour.The x-ray absorption studies indicate that all Co ions in these samples actually substituted into the ZnO lattice without formatting any detectable secondary phase.Compared with weak ferromagnetism(0.16 μB/Co2+) in the Zn0.95Co0.05O single crystalline film with reducing annealing in the absence of Zn vapour,the films annealed in the reducing atmosphere with Zn vapour are found to have much stronger ferromagnetism(0.65 μB/Co2+) at room temperature.This experimental studies clearly indicate that Zn interstitials are more effective than oxygen vacancies to activate the high-temperature ferromagnetism in Co-doped ZnO films,and the corresponding ferromagnetic mechanism is discussed. 相似文献
3.
It is proposed that the magnetization-induced anisotropy of magnetic films of cubic crystal structure originates from the anisotropy of atomic pair ordering, shape anisotropy, and strain anisotropy resulting from the constraint of the magnetostriction strain imposed on the film by the substratc. Calculated are the three anisotropy constants and their sum K vs temperature for Ni, Fe, and 55%Ni-Fe films; the room temperature (RT) constants vs the substrate temperature Tt during deposition or annealing after deposition for Ni and 50%Ni Co films; the RT constants vs com- position fraction for Fe-Ni films with Tt = RT, 250℃ and 450℃, Co Ni films at Tt = RT, 100℃ and 320℃, and Fe-Co films with Tt = RT and 300℃; the spread of RT K vs composition fraction for Fe Ni films; and RT △K/K vs composition fraction for Fe-Ni and Co Ni films, where △K denotes the variation of K of the film that is detached from its substrate. The calculated curves well accord with the measurements. The irrelevancy of K to the substrate material and the fast kinetics of the annealing in a field applied in the direction of the hard axis are explained reasonably.[第一段] 相似文献
4.
Novel material for nonvolatile ovonic unified memory (OUM)-Ag11In12Te26Sb51 phase change semiconductor 下载免费PDF全文
In this paper, Ag_{11}In_{12}Te_{26}Sb_{51} phase change semiconductor films have been prepared by dc sputtering. The crystallization behaviour of amorphous Ag_{11}In_{12}Te_{26}Sb_{51} thin films was investigated by using differential scanning calorimetry and x-ray diffraction. It was found that the crystallization temperature is about 483K and the melting temperature is 754.8K and the activation energy for crystallization, E_a, is 2.07eV. The crystalline Ag_{11}In_{12}Te_{26}Sb_{51} films were obtained using initializer. The initialization conditions have a great effect on the sheet resistance of Ag_{11}In_{12}Te_{26}Sb_{51} films. We found that the effect of the initialization condition on the sheet resistance can be ascribed to the crystallinity of Ag_{11}In_{12}Te_{26}Sb_{51} films. The sheet resistance of the amorphous (R_{amo}) film is found to be larger than 1×10^6Ω and that of the crystalline (R_{cry}) film lies in the range from about 10^3 to 10^4Ω. So we have the ratio R_{amo}/R_{cry}=10^2~10^3, which is sufficiently large for application in memory devices. 相似文献
5.
The dependences of soft magnetic properties and microstructures of the
sputtered FeCo (=FeFeCo薄膜 溅射条件 软磁性 高饱和磁化强度 FeCo film, sputtering conditions, high saturation magnetization,
soft magnetic properties 2005-10-26 3/7/2006 12:00:00 AM The dependences of soft magnetic properties and microstructures of the sputtered FeCo (=Fe65Co35) films on Co underlayer thickness tCo, FeCo thickness tFeCo, substrate temperature Ts and taxget-substrate spacing dT-s are studied. FeCo single layer generally shows a high coercivity with no obvious magnetic anisotropy. Excellent soft magnetic properties with saturation magnetization μ0Ms of 2.35 T and hard axis coercivity Hch of 0.25 kA/m in FeCo films can be achieved by introducing a Co underlayer. It is shown that sandwiching a Co underlayer causes a change in orientation and reduction in grain size from 70 nm to about 10 nm in the FeCo layer. The magnetic softness can be explained by the Hoffmann's ripple theory due to the effect of grain size. The magnetic anisotropy can be controlled by changing dT-S, and a maximum of 14.3 kA/m for anisotropic field Hk is obtained with dT-S=18.0 cm. 相似文献
6.
This paper reports that the K x-ray spectra of the thin target 47Ag, 48Cd, 49In and 50Sn were measured by an HPGe semi-conductor detector in collisions with 84.5 MeV 6C4+ ions. Our experiment revealed the Kα x-ray energy shifts were not obvious and the Kβ1 x-ray energy shifts were about 90~110 eV. The simple model of Burch et al has been previously used to calculate the K x-ray energy shifts due to an additional vacancy in 2p orbit. The present work extends the model of Burch to calculate the x-ray energy shifts of multiple ionized atoms induced by heavy ions with kinetic energy of MeV/u. In addition to our experimental results, many other experimental results are compared with the calculated values by using the model. 相似文献
7.
Rong Zhang 《中国物理 B》2022,31(6):63402-063402
The effect of collision energy on the magnetically tuned $^{6}$Li-$^{6}$Li Feshbach resonance (FR) is investigated theoretically by using the coupled-channel (CC) method for the collision energy ranging from 1 μ$ {\rm K} \cdot {k}_{\rm B}$ to 100 μ$ {\rm K} \cdot {k}_{\rm B}$. At the collision energy of 1 μ$ {\rm K} \cdot {k}_{\rm B}$, the resonance positions calculated are 543.152 Gs (s wave, the unit $1 {\rm Gs}=10^{-4} {\rm T}$), 185.109 Gs (p wave $|m_{l}| = 0$), and 185.113 Gs (p wave $|m_{l}| = 1$), respectively. The p-wave FR near 185 Gs exibits a doublet structure of 4 mGs, associated with dipole-dipole interaction. With the increase of the collision energy, it is found that the splitting width remains the same (4 mGs), and that the resonance positions of s and p waves are shifted to higher magnetic fields with the increase of collision energy. The variations of the other quantities including the resonance width and the amplitude of the total scattering section are also discussed in detail. The thermally averaged elastic rate coefficients at $T=10$, 15, 20, 25 K are calculated and compared. 相似文献
8.
Anomalous magnetic properties of an iron film system deposited on fracture surfaces of α-Al2O3 ceramics 下载免费PDF全文
An iron film percolation system is fabricated by vapour-phase deposition on fracture surfaces of α-Al2O3 ceramics. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurement reveals that the magnetic phase of the film samples evolve from a high-temperature ferromagnetic state to a low-temperature spin-glass-like state, which is also demonstrated by the temperature-dependent ac susceptibility of the iron films. The temperature dependence of the exchange bias field He of the iron film exhibits a minimum peak around the temperature T=5 K, which is independent of the magnitude of the cooling field Hcf. However, for T 〉 10K, (1) He is always negative when Hcf=2kOe and (2) for Hcf= 20 kOe (1Oe≈80 A/m), He changes from negative to positive values as T increases. Our experimental results show that the anomalous hysteresis properties mainly result from the oxide surfaces of the films with spin-glass-like phase. 相似文献
9.
Ru thickness-dependent interlayer coupling and ultrahigh FMR frequency in FeCoB/Ru/FeCoB sandwich trilayers 下载免费PDF全文
The antiferromagnetic (AFM) interlayer coupling effective field in a ferromagnetic/non-magnetic/ferromagnetic (FM/NM/FM) sandwich structure, as a driving force, can dramatically enhance the ferromagnetic resonance (FMR) frequency. Changing the non-magnetic spacer thickness is an effective way to control the interlayer coupling type and intensity, as well as the FMR frequency. In this study, FeCoB/Ru/FeCoB sandwich trilayers with Ru thickness ($t_{\rm Ru}$) ranging from 1 Å to 16 Å are prepared by a compositional gradient sputtering (CGS) method. It is revealed that a stress-induced anisotropy is present in the FeCoB films due to the B composition gradient in the samples. A $t_{\mathrm{Ru}}$-dependent oscillation of interlayer coupling from FM to AFM with two periods is observed. An AFM coupling occurs in a range of $2 {\rm Å} \le t_{\rm Ru} \le 8 {\rm Å}$ and over 16 $\mathrm{Å}$, while an FM coupling is present in a range of $t_{\rm Ru}< 2$ Å and $9 {\rm Å} \le t_{\rm Ru} \le 14.5 Å$. It is interesting that an ultrahigh optical mode (OM) FMR frequency in excess of 20 GHz is obtained in the sample with ${t}_{\mathrm{Ru}}= 2.5 \mathrm{Å}$ under an AFM coupling. The dynamic coupling mechanism in trilayers is simulated, and the corresponding coupling types at different values of $t_{\mathrm{Ru}}$ are verified by Layadi's rigid model. This study provides a controllable way to prepare and investigate the ultrahigh FMR films. 相似文献
10.
Density functional theory is employed to investigate the electronic and structural properties of substitutional Si impurities in a (10,0) BN nanotube. For the Si
case, the band structure shows a level centered on the Si atom crossing the Fermi energy and no net spin is found. The Si
introduces three localized exchange splitted Si levels in the gap. The formation energies show that the Si
is likely to be present at N-rich conditions.Received: 9 December 2003, Published online: 28 May 2004PACS:
61.46. + w Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals - 73.22.-f Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals - 85.35.Kt Nanotube devices 相似文献
11.
Density functional theory (DFT) (B3P86) of Gaussian 03 has been used to optimize the structure of the Cr2 molecule, a transition metal element molecule. The result shows that the ground state for the Cr2 molecule is a 13- multiple state, indicating that there exists a spin polarization effect in the Cr2 molecule. Meanwhile, we have not found any spin pollution because the wave function of the ground state does not mingle with wave functions of higher-energy states. So the ground state for Cr2 molecule being a 13-multiple state is indicative of spin polarization effect of the Cr2 molecule among transition metal elements, that is, there are 12 parallel spin electrons in the Cr2 molecule. The number of non-conjugated electrons is greatest. These electrons occupy different spatial orbitals so that the energy of the Cr2 molecule is minimized. It can be concluded that the effect of parallel spin in the Cr2 molecule is larger than the effect of the conjugated molecule, which is obviously related to the effect of electron d delocalization. In addition, the Murrell Sorbie potential functions with the parameters for the ground state and other states of the Cr2 molecule are derived. The dissociation energy De for the ground state of the Cr2 molecule is 0.1034eV, equilibrium bond length Re is 0.3396 nm, and vibration frequency we is 73.81cm^-1. Its force constants f2, f3 and f4 are 0.0835, -0.2831 and 0.3535 aJ. nm^-4 respectively. The other spectroscopic data for the ground state of the Cr2 molecule ωeχe, Be and αe are 1.2105, 0.0562 and 7.2938 x 10^-4cm^-1 respectively. 相似文献
12.
Growth and transport features of electron-doped superconductor Pr1-xLaCexCuO4-δ thin films 下载免费PDF全文
<正>T’-phase electron-doped superconductor Pr1-xLaCexCuO4-δ(PLCCO) thin films are successfully prepared on SrTiO3(100) substrates by using the dc magnetron sputtering method.It is found that the films each have a highly oriented structure along the c-axis.For optimally doped films with x≈0.10,the superconducting transition temperature Tc is 23.5 K,which is similar to that of a single crystal.The quadratic temperature dependence of the resistivity is observed when T > Tc,which can be attributed to the two-dimensional Fermi liquid behaviour.Besides,the optimal conditions for preparing the T’-phase PLCCO thin films are also discussed in detail. 相似文献
13.
We use the Pair Approximation method to analyze the magnetic and magnetocaloric behaviors of diluted mixed spin ${\rm S_A}$=1 and spin ${\rm S_B}$=1/2 with the anisotropic Heisenberg model, on a cubic lattice with coordination number $z$=6. Our system is described in presence of an external magnetic field; the phase diagram and thermodynamic properties related to the concentration of magnetic atom (A or B) and the single ion anisotropy are constructed and discussed. Special attention is paid to magnetocaloric properties provided by isothermal entropy change as well as the cooling capacity. These cooling power keys are plotted and discussed as a function of interaction anisotropy and magnetic component concentration of two sublattices ions A and B. Numerical results show a double peak structure in the entropy change curve and the inverse magnetocaloric effect related to the presence of the negative single-ion anisotropy. 相似文献
14.
为了研究氢化非晶硅薄膜的稳定性,我们设计了一个在原子氢气氛中热退火的同时进行光诱导退火的实验(TLAH)。实验装置是由传统的微波电子回旋共振化学气相沉积系统改造而成为热丝辅助微波电子回旋共振化学气相沉积系统。为了对这一退火方法进行比较,对样品还进行了热退火、热退火同时进行光诱导退火。同时,为了定量地分析光电导衰退,我们假设光电导衰退遵循扩展指数规律:1/σph=1/σs-(1/σs-1/σ0)exp[-(t/τ)β],这里扩展指数参数β 和时间常数 τ 可从与 lnt 的线性关系中截距和斜率得到, 式中光电导饱和值σs可以通过在对数坐标系中表示的光电导和光照时间关系进行高斯拟合得到。实验结果显示:TLAH 方法可以提高氢化非晶硅薄膜的稳定性、改善其微结构和光电特性,同时还发现,光学带隙明显减小、荧光光谱显著地朝着低能方向移动。 相似文献
15.
This paper reports the experimental results on electromagnetically induced absorption (EIA) spectra observed in the system which does not satisfy completely the conditions given by Lezama et al [1999 Phys. Rev. A 59 4732]. EIA signals on the transitions in the Cs D2 line are able to be observed, where Fg ←→ Fe = Fg-1 as open systems. Theoretical model of Lezama et al is good for the case Fg ←→ Fc = Fg + 1, considering spontaneous transfer of atomic coherences or populations this model is not able to explain our experimental results obtained in the case Fg ←→ Fe = Fg - 1. This paper offers a theoretical model which is able to well explain the case Fg ←→ Fc = Fg - 1. It also uses this theoretical model to explain the split and shift of EIA peaks, which have been obtained in experiments. 相似文献
16.
It has been confirmed that glass-forming ability (GFA) of
supercooled liquids is related to not only liquid phase stability
but also the crystallization resistance. In this paper, it is found
that the liquid region interval ($T_{\rm l}-T_{\rm g})$
characterized by the normalized parameter of $T_{\rm g}$/$T_{\rm l}$
could reflect the stability of glass-forming liquids at the
equilibrium state, whilst the normalization of supercooled liquid
region $\Delta T_{\rm x}$=($T_{\rm x}-T_{\rm g})$, i.e. $\Delta
T_{\rm x}$/$T_{\rm x}$ (wherein $T_{\rm l}$ is the liquidus
temperature, $T_{\rm g}$ the glass transition temperature, and
$T_{\rm x}$ the onset crystallization temperature) could indicate
the crystallization resistance during glass formation. Thus, a new
parameter, defined as $\xi =T_{\rm g}$/$T_{\rm l}+\Delta T_{\rm
x}$/$T_{\rm x}$ is established to predict the GFA of supercooled
liquids. In comparison with other commonly used criteria, this
parameter demonstrates a better statistical correlation with the GFA
for various glass-forming systems including metallic glasses, oxide
glasses and cryoprotectants. 相似文献
17.
It has been confirmed that glass-forming ability (GFA) of supercooled liquids is related to not only liquid phase stability but also the crystallization resistance. In this paper, it is found that the liquid region interval (T1 - Tg) characterized by the normalized parameter of Tg/T1 could reflect the stability of glass-forming liquids at the equilibrium state, whilst the normalization of supercooled liquid region △Tx=(Tx - Tg), i.e. △Tx/Tx (wherein T1 is the liquidus temperature, Tg the glass transition temperature, and Tx the onset crystallization temperature) could indicate the crystallization resistance during glass formation. Thus, a new parameter, defined as ζ = Tg/T1+△Tx/Tx is established to predict the GFA of supercooled liquids. In comparison with other commonly used criteria, this parameter demonstrates a better statistical correlation with the GFA for various glass-forming systems including metallic glasses, oxide glasses and cryoprotectants. 相似文献
18.
Investigations on spectroscopic parameters, vibrational levels, classical turning points and inertial rotation and centrifugal distortion constants for the X1∑+g state of sodium dimer 下载免费PDF全文
The density functional theory (B3LYP, B3P86) and the quadratic
configuration-interaction method including single and double
substitutions (QCISD(T), QCISD) presented in Gaussian03 program
package are employed to calculate the equilibrium internuclear
distance $R_{\rm e}$, the dissociation energy $D_{\rm e }$ and the
harmonic frequency $\omega _{\rm e}$ for the $X{}^{1}\Sigma^{ +
}_{\rm g}$ state of sodium dimer in a number of basis sets. The
conclusion is gained that the best $R_{\rm e}$, $D_{\rm e}$ and
$\omega _{\rm e}$ results can be attained at the
QCISD/6-311G(3df,3pd) level of theory. The potential energy curve at
this level of theory for this state is obtained over a wide
internuclear separation range from 0.16 to 2.0~nm and is fitted to
the analytic Murrell--Sorbie function. The spectroscopic parameters
$D_{\rm e}$, $D_{0}$, $R_{\rm e}$, $\omega _{\rm e}$,
$\omega _{\rm e}\chi _{\rm e}$,
$\alpha _{\rm e}$
and $B_{\rm e}$ are calculated to be 0.7219~eV,
0.7135~eV, 0.31813~nm, 151.63~cm$^{ - 1}$, 0.7288~cm$^{ - 1}$,
0.000729~cm$^{ - 1}$ and 0.1449~cm$^{ - 1}$, respectively, which are in good
agreement with the measurements. With the potential obtained at the
QCISD/6-311G(3df,3pd) level of theory, a total of 63 vibrational
states is found when $J=0$ by solving the radial Schr\"{o}dinger equation
of nuclear motion. The vibrational level, corresponding classical turning
point and inertial rotation constant are computed for each vibrational
state. The centrifugal distortion constants
($D_{\upsilon }\, H_{\upsilon }$,
$L_{\upsilon }$, $M_{\upsilon }$, $N_{\upsilon }$ and $O_{\upsilon })$ are
reported for the first time for the first 31 vibrational states when $J=0$. 相似文献
19.
Effect of substrate temperature on the growth and properties of boron-doped microcrystalline silicon films 下载免费PDF全文
Highly conductive boron-doped hydrogenated microcrystalline silicon (\mu
c-Si:H) films are prepared by very high frequency plasma enhanced chemical
vapour deposition (VHF PECVD) at the substrate temperatures $T_{\rm S})$
ranging
from 90$^\circ$C to 270$^\circ$C. The effects of $T_{\rm S}$ on the growth and
properties of the films are investigated. Results indicate that the growth
rate, the electrical (dark conductivity, carrier concentration and Hall
mobility) and structural (crystallinity and grain size) properties are all
strongly dependent on $T_{\rm S}$. As $T_{\rm S}$ increases, it is
observed that 1)
the growth rate initially increases and then arrives at a maximum value of
13.3 nm/min at $T_{\rm S}$=210$^\circ$C, 2) the crystalline volume fraction
($X_{\rm c})$ and the grain size increase initially, then reach their maximum
values at $T_{\rm S}$=140$^\circ$C, and finally decrease, 3) the dark
conductivity ($\sigma _{\rm d})$, carrier concentration and Hall mobility have
a similar dependence on $T_{\rm S}$ and arrive at their maximum values at
$T_{\rm S}$=190$^\circ$C. In addition, it is also observed that at a lower
substrate temperature $T_{\rm S}$, a higher dopant concentration is required in
order to obtain a maximum $\sigma _{\rm d}$. 相似文献
20.
Xian-Dong Li 《中国物理 B》2022,31(11):110304-110304
The Janus monolayer transition metal dichalcogenides (TMDs) $MXY$ ($M={\rm Mo}$, W, $etc$. and $X, Y={\rm S}$, Se, $etc$.) have been successfully synthesized in recent years. The Rashba spin splitting in these compounds arises due to the breaking of out-of-plane mirror symmetry. Here we study the pairing symmetry of superconducting Janus monolayer TMDs within the weak-coupling framework near critical temperature $T_{\rm c}$, of which the Fermi surface (FS) sheets centered around both $ărGamma$ and $K (K')$ points. We find that the strong Rashba splitting produces two kinds of topological superconducting states which differ from that in its parent compounds. More specifically, at relatively high chemical potentials, we obtain a time-reversal invariant $s + f + p$-wave mixed superconducting state, which is fully gapped and topologically nontrivial, $i.e.$, a $\mathbb{Z}_2$ topological state. On the other hand, a time-reversal symmetry breaking $d + p + f$-wave superconducting state appears at lower chemical potentials. This state possess a large Chern number $|C|=6$ at appropriate pairing strength, demonstrating its nontrivial band topology. Our results suggest the Janus monolayer TMDs to be a promising candidate for the intrinsic helical and chiral topological superconductors. 相似文献