Interfacial Oxygen‐Driven Charge Localization and Plasmon Excitation in Unconventional Superconductors

2020 ◽  
Vol 32 (34) ◽  
pp. 2000153
Author(s):  
Chi Sin Tang ◽  
Xinmao Yin ◽  
Shengwei Zeng ◽  
Jing Wu ◽  
Ming Yang ◽  
...  
Author(s):  
Daniel UGARTE

Small particles exhibit chemical and physical behaviors substantially different from bulk materials. This is due to the fact that boundary conditions can induce specific constraints on the observed properties. As an example, energy loss experiments carried out in an analytical electron microscope, constitute a powerful technique to investigate the excitation of collective surface modes (plasmons), which are modified in a limited size medium. In this work a STEM VG HB501 has been used to study the low energy loss spectrum (1-40 eV) of silicon spherical particles [1], and the spatial localization of the different modes has been analyzed through digitally acquired energy filtered images. This material and its oxides have been extensively studied and are very well characterized, because of their applications in microelectronics. These particles are thus ideal objects to test the validity of theories developed up to now.Typical EELS spectra in the low loss region are shown in fig. 2 and energy filtered images for the main spectral features in fig. 3.


Author(s):  
H. Seiler ◽  
U. Haas ◽  
K.H. Körtje

The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared silver layers evaporated in high vacuum with cluster layers of small silver particles, evaporated in N2 at a pressure of about 102 Pa. The investigations were performed by electron optical methods (TEM, SEM, EELS) and by Photoacoustic (PA) Spectroscopy (gas-microphone detection).The observation of cluster layers with TEM and high resolution SEM show small silver particles with diameters of about 50 nm (Fig. 1 and Figure 2, respectively). The electron diffraction patterns of homogeneous Ag layers and of cluster layers are similar, whereas the low loss EELS spectra due to plasmon excitation are quite different. Fig. 3 and Figure 4 show first results of EELS spectra of a cluster layer of small silver particles on carbon foil and of a homogeneous Ag layer, respectively.


2002 ◽  
Vol 716 ◽  
Author(s):  
D. Jacques ◽  
S. Petitdidier ◽  
J.L. Regolini ◽  
K. Barla

AbstractOxide/Nitride dielectric stack is widely used as the standard dielectric for DRAM capacitors. The influence of the chemical cleaning prior to the stack formation has been studied in this work. As a result, morphological data such as stack surface roughness (Atomic Force Microscopy) and silicon nitride (SiN) incubation time for growth are comparable for all the studied cases on <Si>. However, Tof-SIMS exhibits different oxygen content at the Si/stack interface following the different chemical treatments. Electrical measurements show comparable C-V and I-V results, for the same Equivalent Oxide Thickness (same capacitance at strong accumulation i.e.-3V) while the different studied interfaces bring different interface states density with lower values for higher interfacial oxygen content. For DRAM applications, a clear improvement in electrical characteristics is obtained under low interfacial oxygen content conditions. Results are compared in embedded-DRAM cells for which we developed an industrially compatible dielectric deposition sequence to obtain minimum leakage current with maximum specific capacitance and no particular linking constraints.


2013 ◽  
Vol E96.C (3) ◽  
pp. 385-388 ◽  
Author(s):  
Hathaithip NINSONTI ◽  
Weerasak CHOMKITICHAI ◽  
Akira BABA ◽  
Wiyong KANGWANSUPAMONKON ◽  
Sukon PHANICHPHANT ◽  
...  

2005 ◽  
Vol 480-481 ◽  
pp. 287-292 ◽  
Author(s):  
S.E. Paje ◽  
F. Teran ◽  
J.M. Riveiro ◽  
J. Llopis ◽  
M.A. García ◽  
...  

In this research we study optical absorption and morphology of silver films prepared with a sputtering method. Silver granular films are obtained on a glass substrate for films with thickness smaller than about 60 Å. Superficial silver clusters of around 100 nm in diameter are clearly seen in the atomic force micrographs. The absorption of these samples are characterized by plasmon excitation in the 450-650 nm spectral range, which differs from the known excitation of silver nanoparticles fabricated by different techniques. The optical absorption of silver granular films depend on sputtering conditions like substrate temperature or deposition rate and correlates with the surface morphology.


2017 ◽  
Vol 31 (07) ◽  
pp. 1750071
Author(s):  
Z. D. Vatansever ◽  
S. Sakiroglu ◽  
I. Sokmen

In this paper, the effects of a repulsive scattering center on the ground-state energy and spin properties of a three-electron parabolic quantum dot are investigated theoretically by means of configuration interaction method. Phase transition from a weakly correlated regime to a strongly correlated regime is examined from several strengths and positions of Gaussian impurity. Numerical results reveal that the transition from spin-1/2 to spin-3/2 state depends strongly on the location of the impurity which accordingly states the controllability of the spin polarization. Moreover, broken circular symmetry results in more pronounced electronic charge localization.


Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3393-3402 ◽  
Author(s):  
Yuehong Xu ◽  
Huifang Zhang ◽  
Quan Li ◽  
Xueqian Zhang ◽  
Quan Xu ◽  
...  

AbstractCylindrical vector beams (CVBs), being a special kind of beams with spatially variant states of polarizations, are promising in photonics applications, including high-resolution imaging, plasmon excitation, optical trapping, and laser machining. Recently, generating CVBs using metasurfaces has drawn enormous interest owing to their highly designable, multifunctional, and integratable features. However, related studies remain unexplored in the terahertz regime. Here, a generic method for efficiently generating terahertz CVBs carrying orbital angular momentums (OAMs) is proposed and experimentally demonstrated using transmission-type spatial-variant dielectric metasurfaces, which is realized by designing the interference between the two circularly polarized transmission components. This method is based on spin-decoupled phase control allowed by simultaneously manipulating the dynamic phase and geometric phase of each structure, endowing more degree of freedom in designing the vector beams. Two types of metasurfaces which respectively generate polarization-dependent terahertz vector vortex beams (VVBs) and vector Bessel beams (VBBs) are experimentally characterized. The proposed method opens a new window to generate versatile vector beams, providing new capabilities in developing novel, compact, and high-performance devices applicable to broad electromagnetic spectral regimes.


2021 ◽  
Author(s):  
Xiao‐Long Zhang ◽  
Peng‐Peng Yang ◽  
Ya‐Rong Zheng ◽  
Yu Duan ◽  
Shao‐Jin Hu ◽  
...  

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