Computational Study of Cu-Containing Artificial DNA: Twist Angle Dependence of Magnetism

2016 ◽  
Vol 1 (17) ◽  
pp. 5521-5529
Author(s):  
Yuuichi Orimoto ◽  
Yuriko Aoki
Keyword(s):  
Computational Study ◽  
Twist Angle ◽  
Angle Dependence ◽  
Artificial Dna ◽  
Dna Twist

scholarly journals Twist-angle dependence of moiré excitons in WS2/MoSe2 heterobilayers

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Long Zhang ◽  
Zhe Zhang ◽  
Fengcheng Wu ◽  
Danqing Wang ◽  
Rahul Gogna ◽  
...  
Keyword(s):  
Experimental Study ◽  
Effective Mass ◽  
Critical Parameter ◽  
Twist Angle ◽  
Van Der Waals ◽  
Reciprocal Lattice ◽  
Lattice Period ◽  
Van Der Waals Heterostructures ◽  
Angle Dependence ◽  
The Way

AbstractMoiré lattices formed in twisted van der Waals bilayers provide a unique, tunable platform to realize coupled electron or exciton lattices unavailable before. While twist angle between the bilayer has been shown to be a critical parameter in engineering the moiré potential and enabling novel phenomena in electronic moiré systems, a systematic experimental study as a function of twist angle is still missing. Here we show that not only are moiré excitons robust in bilayers of even large twist angles, but also properties of the moiré excitons are dependant on, and controllable by, the moiré reciprocal lattice period via twist-angle tuning. From the twist-angle dependence, we furthermore obtain the effective mass of the interlayer excitons and the electron inter-layer tunneling strength, which are difficult to measure experimentally otherwise. These findings pave the way for understanding and engineering rich moiré-lattice induced phenomena in angle-twisted semiconductor van der Waals heterostructures.

Twist-angle Dependence of the Ground Exciton Energy in Twisted Bilayer MoS$_2$

2020 ◽  
Vol 70 (12) ◽  
pp. 1117-1121
Author(s):  
Junkyoung KIM ◽  
Haeun CHA ◽  
Inwoo PARK ◽  
Gang Hee HAN* ◽  
Seung Ryong PARK ◽  
...  
Keyword(s):  
Twist Angle ◽  
Exciton Energy ◽  
Angle Dependence

scholarly journals Angle-tunable intersubband photoabsorption and enhanced photobleaching in twisted bilayer graphene

Nano Research ◽  
2021 ◽  
Author(s):  
Eva A. A. Pogna ◽  
Xianchong Miao ◽  
Driele von Dreifus ◽  
Thonimar V. Alencar ◽  
Marcus V. O. Moutinho ◽  
...  
Keyword(s):  
Electronic Band Structure ◽  
Twist Angle ◽  
Interlayer Coupling ◽  
Bilayer Graphene ◽  
Relaxation Dynamics ◽  
Carrier Distribution ◽  
Absorption Bands ◽  
Electronic Band ◽  
Angle Dependence ◽  
Twisted Bilayer Graphene

AbstractVan der Waals heterostructures obtained by artificially stacking two-dimensional crystals represent the frontier of material engineering, demonstrating properties superior to those of the starting materials. Fine control of the interlayer twist angle has opened new possibilities for tailoring the optoelectronic properties of these heterostructures. Twisted bilayer graphene with a strong interlayer coupling is a prototype of twisted heterostructure inheriting the intriguing electronic properties of graphene. Understanding the effects of the twist angle on its out-of-equilibrium optical properties is crucial for devising optoelectronic applications. With this aim, we here combine excitation-resolved hot photoluminescence with femtosecond transient absorption microscopy. The hot charge carrier distribution induced by photo-excitation results in peaked absorption bleaching and photo-induced absorption bands, both with pronounced twist angle dependence. Theoretical simulations of the electronic band structure and of the joint density of states enable to assign these bands to the blocking of interband transitions at the van Hove singularities and to photo-activated intersubband transitions. The tens of picoseconds relaxation dynamics of the observed bands is attributed to the angle-dependence of electron and phonon heat capacities of twisted bilayer graphene.

scholarly journals Formation and tuning of moiré excitons in large-twist angle WS2/MoSe2 heterobilayers

2020 ◽  
Author(s):  
Long Zhang ◽  
Zhe Zhang ◽  
Fengcheng Wu ◽  
Danqing Wang ◽  
Rahul Gogna ◽  
...  
Keyword(s):  
Effective Mass ◽  
Analytical Model ◽  
Critical Parameter ◽  
Twist Angle ◽  
Van Der Waals ◽  
Reciprocal Lattice ◽  
Semiconductor Heterostructures ◽  
Angle Dependence ◽  
Systems Studies ◽  
Umklapp Scattering

Abstract Moire lattices formed in twisted van der Waals bilayers provide a unique, tunable platform to realize coupled electron or exciton lattices unavailable before. While twist angle between the bilayer has been shown to be a critical parameter in engineering the moire potential and enabling novel phenomena in electronic moire systems, studies of moire excitons so far have focused on closely angularly-aligned heterobilayers. The twist-angle degree of freedom has been largely considered detrimental to the observation of moire excitons. Here we report robust moire excitons in bilayers of even large twist angles formed due to Umklapp scattering by the moire reciprocal lattice vectors, and we furthermore demonstrate twist-angle tuning of the properties of the moire excitons as a result of varying moire reciprocal lattice periods. We develop an intuitive analytical model to explain our results, and, from the twist-angle dependence, obtain the effective mass of the interlayer excitons and the electron inter-layer tunneling strength, which are difficult to measure experimentally otherwise. These findings pave the way for understanding and engineering rich moire -lattice induced phenomena in angle-twisted semiconductor van der Waals semiconductor heterostructures.

Scattering-angle dependence of signal/background ratio of inner-shell electron excitation loss in EELS

1983 ◽  
Vol 41 ◽  
pp. 390-391
Author(s):  
T. Oikawa ◽  
M. Inoue ◽  
T. Honda ◽  
Y. Kokubo
Keyword(s):  
Energy Loss ◽  
Electron Excitation ◽  
Heavy Elements ◽  
Background Intensity ◽  
Light Elements ◽  
Energy Analyzer ◽  
High Background ◽  
Scattering Angle ◽  
Angle Dependence ◽  
Shell Electron

EELS allows us to make analysis of light elements such as hydrogen to heavy elements of microareas on the specimen. In energy loss spectra, however, elemental signals ride on a high background; therefore, the signal/background (S/B) ratio is very low in EELS. A technique which collects the center beam axial-symmetrically in the scattering angle is generally used to obtain high total intensity. However, the technique collects high background intensity together with elemental signals; therefore, the technique does not improve the S/B ratio. This report presents the experimental results of the S/B ratio measured as a function of the scattering angle and shows the possibility of the S/B ratio being improved in the high scattering angle range.Energy loss spectra have been measured using a JEM-200CX TEM with an energy analyzer ASEA3 at 200 kV.Fig.l shows a typical K-shell electron excitation edge riding on background in an energy loss spectrum.

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