Articles you may be interested inThermal Si O 2 gated Ge metal-oxide-semiconductor capacitor on Si substrate formed by thin amorphous Ge oxidation and thermal annealing Appl. Phys. Lett. 93, 083506 (2008); 10.1063/1.2976327Characterization and modeling of fast traps in thermal agglomerating germanium nanocrystal metal-oxidesemiconductor capacitor J. Appl. Phys.Observation of memory effect in germanium nanocrystals embedded in an amorphous silicon oxide matrix of a metal-insulator-semiconductor structure
We investigated the optical properties of (Ca,Sr)RuO3 films on the borderline of a metal-insulator (M-I) transition. Our results show all of the predicted characteristics for a metallic Mott-Hubbard system, including (i) a mass enhancement in dc-limit, (ii) an U/2 excitation, and (iii) an U excitation. Also, a self-consistency is found within the Gutzwiller-Brinkman-Rice picture for the Mott transition. Our finding displays that electron correlation should be important even in 4d materials.PACS numbers: 71.30.+h, 71.27.+a, 71.10.Fd, Correlation between electrons in transition and rare earth metal compounds has attracted lots of attentions. In general, the more localized the electron wave function is, the stronger the correlation effects are. As a result, correlation effects are believed to be much more important in describing 3d electrons than 4d or 5d electrons.A metal-insulator (M-I) transition driven by electron correlation was proposed by Mott and subsequently investigated intensively.[1] Since the Hubbard model was proposed in early 1960's, it has been widely accepted as the simplest model which can describe correlation effects. Although the model is composed of only two parameters, i.e. inter-site hopping energy t (= W/z) and on-site Coulomb repulsive energy U , it has not been exactly solved yet except for one dimensional case. [W and z are the bandwidth and the coordination number, respectively.] Up to several years ago, different approaches provided limited insights into different aspects of the M-I transition. However, recent theoretical progresses, including a slave-boson approach, infinite dimension limit approaches with several techniques, and numerical calculations for finite size systems, started to provide a coherent picture. [2] According to the traditional Gutzwiller-BrinkmanRice (GBR) picture, [3] the Mott M-I transition from a metallic side can be described by narrowing and disappearing of a Fermi liquid quasi-particle (QP) band at a critical value of correlation strength, (U/W ) c . Under this strong renormalization, an effective mass, m * , [4] of the QP is related by:Recent theoretical works predict that one particle spectral function A(ω) for the metallic phase will be split into lower (LHB) and upper (UHB) Hubbard bands, in addition to the QP band located at zero frequency. Fig. 1(a) shows the schematic diagram of A(ω). Then, the corresponding optical conductivity spectra σ 1 (ω) can be easily predicted and displayed in Fig. 1(b). Note that σ 1 (ω) in a metallic side has three pronounced features: (i) a "QP peak" near zero frequency, (ii) an "U/2 peak" due to optical transitions between QP band and LHB (or UHB), and (iii) an "U peak" due to a transition between LHB and UHB.FIG. 1. Schematic diagrams of (a) one particle spectral function and (b) optical conductivity, for 4/6-filled metallic Mott-Hubbard system. Dotted lines indicate the contributions from O(2p) band.In this letter, we will report optical properties of (Ca,Sr)RuO 3 films, where four electrons occupy triply degenerate t 2g...
We developed step edge decoration method for the fabrication of semiconductor ZnO nanodots and nanowires using pulsed laser deposition. We synthesized high quality ZnO nanowires with the small diameter of about 20nm and the uniform interval of about 80nm between each nanowire, which has a simple structure for the formation of contact electrodes. The ZnO nanowire-based sensor was prepared only with the simple process of a gold electrode formation. The ZnO nanowire-based sensor exhibited the high surface-to-volume ratio of 58.6μm−1 and the significantly high sensitivity of about 10 even for the low ethanol concentration of 0.2ppm.
We report a bistable resistance switching behavior of CuO thin films. To understand the resistance switching mechanism, we have studied impedance spectroscopy and nanoscale electrical property. From the frequency-dependent impedance properties of CuO thin films in high resistance (ROFF) and low resistance (RON) states, we infer the formation of conducting paths generated by external bias as a possible origin of the bistable resistance states. In addition, the observation of inhomogeneous conducting path using a conducting atomic force microscope is also consistent with our inference.
Articles you may be interested inLarge magnetocaloric effect with a wide working temperature span in the R2CoGa3 (R=Gd, Dy, and Ho) compounds Large magnetocaloric effects over a wide temperature range in MnCo1−xZnxGe Magnetocaloric effect of Ho-, Dy-, and Er-based bulk metallic glasses in helium and hydrogen liquefaction temperature range Appl.The compound Ho 2 In exhibits two successive magnetic phase transitions: a spin-reorientation transition at T SR = 32 K and a magnetic-ordering transition at T C = 85 K. The maximum reversible −⌬S M values are 6.3 and 11.2 J/kg K at T SR and T C , respectively, for a field change of 5 T. These two −⌬S M peaks with the same sign are partly overlapping, which results in a wide temperature interval with appreciable magnetocaloric effect. The results on Ho 2 In indicate that materials with successive SR and magnetic-ordering transitions may constitute an important new class of magnetic refrigerants since they work in a wider temperature range than the conventional refrigerant materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.