Size effect of quantum conductance in carbon nanotube Y-Junctions

This paper studies the quantum conductance properties of three-terminated carbon nanotube Y-junctions, which are built by connecting three （5,5） single-walled carbon nanotubes. The results show that the quantum conductance at the Fermi energy oscillates periodically with the junction＇s size, and the number of oscillating periodic layers is 3 which is the same as that in the two terminated （10, 0）/m（5, 5）/（10, 0） junctions. Moreover, this Y-junction with different size exhibits an obviously different distribution of electron current in the two drain branches, called shunt valve effect of electronic current. Thus the degree of this effect can be controlled and modulated directly by constructing the three branches＇ sizes or the distribution of defect. The results show in detail that the difference between the two drain currents can be up to two times for some constructions with special sizes. In addition, the uniform distribution of defects in the Y-junction leads to lower quantum conductance than that of other defect configurations.

Quantum conductance of armchair carbon nanocoils: roles of geometry effects

Armchair carbon nanocoils (CNCs) with different geometric parameters are constructed and optimized using a tight-binding (TB) total energy model. The quantum conductance of these nanocoils is simulated employing a π-orbital TB model incorporated with the non-equilibrium Green's function theory. Compared with the perfect armchair carbon nanotubes (CNTs) and armchair CNTs with only Stone-Wales (SW) defects, the quantum conductance spectra of the armchair CNCs present distinct gaps around the Fermi level, which are mainly originated from the existence of sp3 carbon in the three-dimensional spiral structures. Moreover, the detailed conductance spectra of the armchair CNCs depend sensitively on their geometric parameters, such as tubular diameter and block-block distance.

The role of oxygen vacancies in the high cycling endurance and quantum conductance in BiVO4-based resistive switching memory

Resistive random access memory(RRAM)has emerged as a new discipline promoting the development of new materials and devices toward a broad range of electronic and energy applications.Here,we realized a memristive device with weak dependence on the top electrodes and demonstrated the quantized conductance(QC)nature in BiVO4 matrix.The electronic properties have been investigated by the measurements of I-V curves,where the resistive switching(RS)phenomenon with stable switching ratio and excellent longterm retention capabilities are identified.Two more inert materials,TiN and Pd,are applied as the top electrodes to exclude the influence of electrodes on the RS states and QC behavior.The X-ray photoelectron spectroscopy results and transport measurements reveal that the conductive filament(CF)is composed by elemental bismuth.The naturally existed oxygen vacancies in BiVO4 matrix plays as the role of catalyst in the formation and dissolution of CF in BiVO4-based RRAM device,which is the primary cause for the observed weak dependence of switching performance in this device on the type of top electrodes.Our results clearly illustrate that BiVO4 could be a new idea platform to realize the high scalability,high cycling endurance,and multilevel storage RRAM devices.

Applications of Quantum Physics on Resistivity, Dielectricity, Giant Magneto Resistance, Hall Effect and Conductance

Quantum theory with conjecture of fractional charge quantization, eigenfunctions for fractional charge quantization, fractional Fourier transform, Hermite function for fractional charge quantization, and eigenfunction for a twisted and twigged electron quanta is developed and applied to resistivity, dielectricity, giant magneto resistance, Hall effect and conductance. Our theoretical relationship for quantum measurements is in good conformity and in agreement with most of the experimental results. These relationships will pave a new approach to quantum physics for deciphering measurements on single quantum particles without destroying them. Our results are in agreement with 2012 Physics Nobel Prize winning Scientists, Serge Haroche and David J. Wineland.

Novel conductance step in carbon nanotube with wing-like zigzag graphene nanoribbons

Connecting one armchair carbon nanotube（CNT） to several zigzag graphene nanoribbons（ZGNRs） we find that the topologically-protected edge states of ZGNRs and the massless Dirac particle inherited from CNT still hold from the analysis of the band structure and the edge state. Furthermore, the lowest conductance step at the valley bottom increases proportionally with increasing the number of ZGNR wings. A novel conductance step of a peak occurs in the valley, which is two steps higher than the lowest step at the valley bottom. In addition, with increasing the number of ZGNR wings the width of the novel conductance step becomes narrow.

Resistive switching effects in oxide sandwiched structures

Resistive switching （RS） behaviors have attracted great interest due to their promising potential for the data storage. Among various materials, oxide-based devices appear to be more advantageous considering their handy fabrication and compatibility with CMOS technology, though the underlying mechanism is still controversial due to the diversity of RS behaviors. In this review, we focus on the oxide-based RS memories, in which the working mechanism can be understood basically according to a so-called filament model. The filaments formation/rupture processes, approaches developed to detect and characterize filaments, several effective attempts to improve the performances of RS and the quantum conductance behaviors in oxide-based resistive random access memory （RRAM） devices are addressed, respectively.