We study the charge transport properties of the spin-selective Andreev reflection(SSAR)effect between a spin polarized scanning tunneling microscope(STM)tip and a Majorana zero mode(MZM).Considering both the MZM and t...We study the charge transport properties of the spin-selective Andreev reflection(SSAR)effect between a spin polarized scanning tunneling microscope(STM)tip and a Majorana zero mode(MZM).Considering both the MZM and the excited states,we calculate the conductance and the shot noise power of the noncollinear SSAR using scattering theory.We find that the excited states give rise to inside peaks.Moreover,we numerically calculate the shot noise power and the Fano factor of the SSAR effect.Our calculation shows that the shot noise power and the Fano factor are related to the angle between the spin polarization direction of the STM tip and that of the MZM,which provide additional characteristics to detect the MZM via SSAR.展开更多
The preparation and electrical properties of diamond nanocones are reviewed, including a maskless etching pro- cess and mechanism of large-area diamond conical nanostructure arrays using a hot filament chemical vapor ...The preparation and electrical properties of diamond nanocones are reviewed, including a maskless etching pro- cess and mechanism of large-area diamond conical nanostructure arrays using a hot filament chemical vapor deposition （HFCVD） system with negatively biased substrates, and the field electron emission, gas sensing, and quantum transport properties of a diamond nanocone array or an individual diamond nanocone. Optimal cone aspect ratio and array density are investigated, along with the relationships between the cone morphologies and experimental parameters, such as the CH4/H2 ratio of the etching gas, the bias current, and the gas pressure. The reviewed experiments demonstrate the possi- bility of using nanostructured diamond cones as a display device element, a point electron emission source, a gas sensor or a quantum device.展开更多
This work reveals the giant influence of spatial distribution of disordered surface roughness on electron tunneling,which is of immediate relevance to the magneto tunnel device and imaging technologies.We calculate th...This work reveals the giant influence of spatial distribution of disordered surface roughness on electron tunneling,which is of immediate relevance to the magneto tunnel device and imaging technologies.We calculate the spin-dependent tunneling in Fe/vacuum/Fe junction with disordered surface roughness with the first-principles non-equilibrium dynamical cluster theory.It is found that,at high concentration of surface roughness,different spatial distributions,including the clustered,anti-clustered and completely random roughness characterized by Warren–Cowley parameters,present large deviations from each other in all spin channels.By changing from clustered to anti-clustered roughness,it is surprising that spin polarization of tunneling in parallel configuration(PC)can be drastically reversed from-0.52 to 0.93,while complete randomness almost eliminates the polarization.It is found that the anti-clustered roughness can dramatically quench the tunneling of minority spin in both PC and anti-PC by orders of magnitude,but significantly enhance the transmission of majority spin in PC(by as large as 40%)compared to the results of clustered roughness,presenting distinct influences of differently correlated surface roughness.The spatial correlation of disordered surface roughness can significantly modify the surface resonance of Fe minority spin.展开更多
The dependence of giant magnetoresistance of sputtered granular type(Co-Ag)/Ag multilayers on the thickness of Ag layers and magnetic layers with varying Co content in the magnetic layers was studied.The magnetoresist...The dependence of giant magnetoresistance of sputtered granular type(Co-Ag)/Ag multilayers on the thickness of Ag layers and magnetic layers with varying Co content in the magnetic layers was studied.The magnetoresistance ratioΔR/R was found to be enhanced by 2-7 times comparing with the single layer granular films.The enhancement was explained by the antiferromagnetic coupling due to magnetostatic interaction between the Co clusters in neighboring magnetic layers.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11674028,61774017,11734004 and 21421003the National Key Research and Development Program of China under Grant No 2017YFA0303300
文摘We study the charge transport properties of the spin-selective Andreev reflection(SSAR)effect between a spin polarized scanning tunneling microscope(STM)tip and a Majorana zero mode(MZM).Considering both the MZM and the excited states,we calculate the conductance and the shot noise power of the noncollinear SSAR using scattering theory.We find that the excited states give rise to inside peaks.Moreover,we numerically calculate the shot noise power and the Fano factor of the SSAR effect.Our calculation shows that the shot noise power and the Fano factor are related to the angle between the spin polarization direction of the STM tip and that of the MZM,which provide additional characteristics to detect the MZM via SSAR.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51272278, 11174362, and 91023041)the National Basic Research Program of China (Grant No. 2009CB930502)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KJCX2-EW-W02)
文摘The preparation and electrical properties of diamond nanocones are reviewed, including a maskless etching pro- cess and mechanism of large-area diamond conical nanostructure arrays using a hot filament chemical vapor deposition （HFCVD） system with negatively biased substrates, and the field electron emission, gas sensing, and quantum transport properties of a diamond nanocone array or an individual diamond nanocone. Optimal cone aspect ratio and array density are investigated, along with the relationships between the cone morphologies and experimental parameters, such as the CH4/H2 ratio of the etching gas, the bias current, and the gas pressure. The reviewed experiments demonstrate the possi- bility of using nanostructured diamond cones as a display device element, a point electron emission source, a gas sensor or a quantum device.
基金financial support from the National Natural Science Foundation of China(Grant No.11874265)Shanghaitech Startup+1 种基金supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0303300 and 2018YFB0407601)the National Natural Science Foundation of China(Grant Nos.11734004 and 21421003)。
文摘This work reveals the giant influence of spatial distribution of disordered surface roughness on electron tunneling,which is of immediate relevance to the magneto tunnel device and imaging technologies.We calculate the spin-dependent tunneling in Fe/vacuum/Fe junction with disordered surface roughness with the first-principles non-equilibrium dynamical cluster theory.It is found that,at high concentration of surface roughness,different spatial distributions,including the clustered,anti-clustered and completely random roughness characterized by Warren–Cowley parameters,present large deviations from each other in all spin channels.By changing from clustered to anti-clustered roughness,it is surprising that spin polarization of tunneling in parallel configuration(PC)can be drastically reversed from-0.52 to 0.93,while complete randomness almost eliminates the polarization.It is found that the anti-clustered roughness can dramatically quench the tunneling of minority spin in both PC and anti-PC by orders of magnitude,but significantly enhance the transmission of majority spin in PC(by as large as 40%)compared to the results of clustered roughness,presenting distinct influences of differently correlated surface roughness.The spatial correlation of disordered surface roughness can significantly modify the surface resonance of Fe minority spin.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19754001 and 59392800,and Shanghai Research Center for Applied Physics.
文摘The dependence of giant magnetoresistance of sputtered granular type(Co-Ag)/Ag multilayers on the thickness of Ag layers and magnetic layers with varying Co content in the magnetic layers was studied.The magnetoresistance ratioΔR/R was found to be enhanced by 2-7 times comparing with the single layer granular films.The enhancement was explained by the antiferromagnetic coupling due to magnetostatic interaction between the Co clusters in neighboring magnetic layers.
