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排序方式: 共有193条查询结果,搜索用时 31 毫秒
11.
Dr. Guanjun Xiao Dr. Chunye Zhu Prof. Yanming Ma Prof. Bingbing Liu Prof. Guangtian Zou Prof. Bo Zou 《Angewandte Chemie (International ed. in English)》2014,53(3):729-733
There is an urgent need for the development in the field of the magnetism of topological insulators, owing to the necessity for the realization of the quantum anomalous Hall effect. Herein, we discuss experimentally fabricated nanostructured hierarchical architectures of the topological insulator Bi2Te3 without the introduction of any exotic magnetic dopants, in which intriguing room‐temperature ferromagnetism was identified. First‐principles calculations demonstrated that the intrinsic point defect with respect to the antisite Te site is responsible for the creation of a magnetic moment. Such a mechanism, which is different from that of a vacancy defect, provides new insights into the origins of magnetism. Our findings may pave the way for developing future Bi2Te3‐based dissipationless spintronics and fault‐tolerant quantum computation. 相似文献
12.
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The proposal of higher-order topology leads to intriguing wave propagation properties beyond the conventional bulk-boundary principle in condensed matter physics. Theoretical and experimental models have been conducted to reveal exotic higher-order hinge and corner states in lower dimensions. Meanwhile, this concept is extended to semimetals and verified in platforms like acoustic and photonic systems. However, most existing schemes are confined to Cn-symmetric-like frameworks. Here a phononic higher-order Weyl semimetal (HOWSM) is put forward by introductions of artificial gauge flux shape. Distinguished from most existing schemes, the traditional two-dimensional lattice with a vertical screw-extending operation is deformed, which guarantees the emergence of higher-order Weyl points. The invariant index is utilized to measure different phases between non-trivial topological and normal insulators visibly. Simulation results indicate that the structure supports robust hinge wave transmission in a piling sample. This work brings new approaches for constructing HOWSMs and enriches the potential applications in manufacturing high-performance acoustic devices. 相似文献
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15.
Summary The dielectric and electronic properties of thianthren (C6H4(S)2H4C6) are determined by means of optical reflectivity, absorption measurements and reflection electron energy loss spectroscopy.
The experimental results are interpreted on the basis of a Complete Neglect of Differential Overlap (CNDO) calculation used
in three different parametrization schemes. Emphasis is laid on the discussion of the problems which generally affect the
analysis of electron energy loss spectra, and a procedure to obtain the complex dielectric function from electron energy loss
measurements performed in the reflection mode is suggested.
Work partially supported by the MURST through the GNSM. 相似文献
16.
17.
K. P. Ghatak 《Il Nuovo Cimento D》1991,13(10):1321-1324
Summary An attempt is made to formulate the thermoelectric power under strong magnetic quantization (TPM) in superlattices (SLS) of
III–V semiconductors with graded structures and to compare the same with that of the forming materials. It is found, taking
Ga0.8In0.14P0.78Sb0.22/GaAs SL as an example, that the TPM increases with increasing quantizing magnetic field and decreases with increasing electron
concentration respectively in an oscillatory manner. The TPM in SL with graded structures is greater than that of the constituent
bulk materials for III–V SL. 相似文献
18.
Summary A calculation method for the scattering cross-section σ of charged carriers on radiation-induced cluster defects has been
developed using a spherical cluster model with rectangular potential barrier shape, of radius and height of 15 nm and 0.6
eV, respectively. Values of the cluster cross-section around 2·10−11 cm2 have been obtained for charged carrier energies from 10−4 eV to over 600 eV. Applying the relaxation-time approximation of the Boltzmann equation, the influence of clusters on silicon
transport properties has been observed to be close to the acoustic-phonon one. The dependence of the Hall factor on radiation-induced
clusters has been determined numerically for temperatures ranging from 5 K to 400 K. The results indicate that the presence
of clusters of such dimensions would not change significantly the Hall coefficientR
H. 相似文献
19.
Analysis of ALD-processed thin films by ion-beam techniques 总被引:1,自引:0,他引:1
Putkonen M Sajavaara T Niinistö L Keinonen J 《Analytical and bioanalytical chemistry》2005,382(8):1791-1799
This review introduces the possibilities of ion-beam techniques for the analysis of thin films and thin-film structures processed by atomic layer deposition (ALD). The characteristic features of ALD are also presented. The analytical techniques discussed include RBS, NRA and ERDA with its variants, viz. the TOF-ERDA and HI-ERDA. The thin film examples are taken from flat-panel display technology (TFEL structures) and the semiconductor industry (high-k insulators).Dedicated to the memory of Wilhelm Fresenius 相似文献
20.
Summary The variational method is used in finding the solution of the transport equation for a system of hot electrons inn-Ge atT=20 K in the presence of high electric field. The role of the emission of optical phonons by hot electrons together with the
effect of electron capture by repulsive centres on the formulation of the distribution function are studied. It is shown that
the emission of optical phonons plays a dominant role in the formulation of the distribution. The influence of electron capture
is very small, it may become appreciable at higher trap concentrations. The obtained distribution function is then used in
calculating the capture rate of electrons by negatively charged centres. It is shown that the capture rate increases with
electric field.
Riassunto Il metodo variazionale è usato per trovare la soluzione dell'equazione di transporto per un sistema di elettroni caldi inn-Ge aT=20 K in presenza di grande campo elettrico. Si studiano il ruolo dell'emissione di fononi ottici da elettroni caldi insieme con l'effetto della cattura degli elettroni da centri di repulsione sulla formulazione della funzione di distribuzione. Si mostra che l'emissione di fononi ottici svolge un ruolo dominante nella formulazione della distribuzione. L'influenza della cattura degli elettroni è molto piccola, può diventare apprezzabile a piú grande concentrazione di trappole. La funzione di distribuzione ottenuta è quindi usata nel calcolare il rapporto di cattura degli elettroni da centri a carica negativa. Si mostra che il rapporto di cattura cresce col campo elettrico.
Резюме Используется вариационный метод для нахождения решения транспортного уравнения для системы горячих электронов вn-Ge приT=20 К при наличии сильного электрического поля. Исследуется роля испускания оптических фононов горячими электронами и эффект эахвата электпонов отталкивающими центрами при определении функции распредения. Показывается, что испускание оптических фононов играет доминируюэую роль при образовании функции распределения. Влияние захвата электронов очень мало и становится существенным при более высоких концентрациях ловушек. Полученная функция распределения используется при вычис-лении интенсивности захвата злектпонов отрицательно заряженными центрами. Показывается, что интенсивность захвата увеличивается с возрастанием электрического поля.相似文献