Density functional theory based computational study has been conducted in order to investigate the effect of substitution of Cr and Co components by Si on the structure, mechanical, electronic, and magnetic properties of the high entropy alloy CrCoNiFe. It is found that the presence of a moderate concentration of Si substitutes (up to 12.5 %) does not significantly reduce the structural and mechanical stability of CrCoNiFe while it may modify its electronic and magnetic properties. Based on that, Si is proposed as a cheap and functional material for partial substitution of Cr or Co in CrCoNiFe.
InGaN is an ideal alloy system for optoelectronic devices due its tunable band gap. Yet high-quality InGaN requires high In concentration, which is a challenging issue that limits its use in green-light LEDs and other devices. In this paper, we investigated the surfactant effect of Sb on the In incorporation on InGaN (000-1) surface via first-principles approaches. Surface phase diagram was also constructed to determine surface structures under different growth conditions. By analyzing surface stress under different structures, we found that Sb adatom can induce tensile sites in the cation lay…
Recently, an experimental study developed an efficient way to obtain sulfur-doped gamma-graphdiyne. This study has shown that this new material could have promising applications in lithium-ion batteries, but the complete understanding of how the sulfur atoms are incorporated into the graphdiyne network is still missing. In this work, we have investigated the sulfur doping process through molecular dynamics and density functional theory simulations. Our results suggest that the doped induced distortions of the gamma-graphdiyne pores prevent the incorporation of more than two sulfur atoms. The m…
Incorporation of surface correction and anharmonic correction to vacancy formation energy for nickel and copper: bridging the gap between Density Functional Theory and experiment
The incorporation site of Er dopants inserted at high and low concentration (respectively 5 and 0.5 mol %) in nanoparticles of CaF 2 is studied by X-ray Absorption Spectroscopy (XAS) at the Er L III edge. The experimental data are compared with the results of structural modeling based on Density Functional Theory (DFT). DFT-based molecular dynamics is also used to simulate complete theoretical EXAFS spectra of the model structures. The results is that Er substitutes for Ca in the structure and in the low concentration case the dopant ions are isolated. At high concentration the rare earth ions…
While the phenomenon of metal substrate adatom incorporation into molecular overlayers is generally believed to occur in several systems, the experimental evidence for this relies on the interpretation of scanning tunnelling microscopy (STM) images, which can be ambiguous and provides no quantitative structural information. We show that surface X-ray diffraction (SXRD) uniquely provides unambiguous identification of these metal adatoms. We present the results of a detailed structural study of the Au(111)-F4TCNQ system, combining surface characterisation by STM, low energy electron diffraction …
The ability to control carrier concentration based on the extent of Cu solubility in the $\mathrm{Cu_{2x}Hg_{2-x}GeTe_4}$ alloy compound (where 0 $\leq$ x $\leq$ 1) makes $\mathrm{Cu_{2x}Hg_{2-x}GeTe_4}$ an interesting case study in the field of thermoelectrics. While Cu clearly plays a role in this process, it is unknown exactly how Cu incorporates into the $\mathrm{Cu_{2x}Hg_{2-x}GeTe_4}$ crystal structure and how this affects the carrier concentration. In this work, we use a combination of resonant energy X-ray diffraction (REXD) experiments and density functional theory (DFT) calculations …
Doping of Si using the scanning probe hydrogen depassivation lithography technique has been shown to enable placing and positioning small numbers of P atoms with nanometer accuracy. Several groups have now used this capability to build devices that exhibit desired quantum behavior determined by their atomistic details. What remains elusive, however, is the ability to control the precise number of atoms placed at a chosen site with 100% yield, thereby limiting the complexity and degree of perfection achievable. As an important step towards precise control of dopant number, we explore the adsorp…
Thiophene oligomers are an important class of organic materials for photovoltaic applications, owing to their unique optoelectronic properties. Recently it was suggested that incorporation of furan units to the thiophene chains, maintaining the chain structure, namely thienylfuran linear oligomers, can bring improvements to the final material. In this work, we present a theoretical study of thiophene, furan and thienylfuran short chains, up to 4 units. Structural and electronic properties were obtained using Hartree-Fock (HF) and Density Functional Theory (DFT) calculations plus beyond mean-fi…
In a data-driven paradigm, machine learning (ML) is the central component for developing accurate and universal exchange-correlation (XC) functionals in density functional theory (DFT). It is well known that XC functionals must satisfy several exact conditions and physical constraints, such as density scaling, spin scaling, and derivative discontinuity. In this work, we demonstrate that contrastive learning is a computationally efficient and flexible method to incorporate a physical constraint in ML-based density functional design. We propose a schematic approach to incorporate the uniform den…
Spin-Dependent Nonorthogonal Generalized Wannier Functions and their Integration with PAW and Hubbard Corrections in Linear-Scaling DFT
University of Warwick（华威大学）；University of Southampton（南安普顿大学）；Trinity College Dublin, The University of Dublin（都柏林三一学院，都柏林大学）；Gdańsk University of Technology（格但斯克理工大学）
Active learning of collinear magnetic Moment Tensor Potentials using the spin-MLIP package from soft-constrained spin-polarized DFT calculations: a case study of Fe-Pd
Skolkovo Institute of Science and Technology（斯科尔科沃科学技术研究所）；HSE University, Faculty of Computer Science（高等经济大学计算机科学学院）；California Institute of Technology（加州理工学院）
We used DFT to study the energetics of the decomposition of alane, AlH3, on the Si(001) surface, as the acceptor complement to PH3. Alane forms a dative bond with the raised atoms of silicon surface dimers, via the Si atom lone pair. We calculated the energies of various structures along the pathway of successive dehydrogenation events following adsorption: AlH2, AlH and Al, finding a gradual, significant decrease in energy. For each stage, we analyse the structure and bonding, and present simulated STM images of the lowest energy structures. Finally, we find that the energy of Al atoms incorp…
We investigate the electronic structure and defect properties of Sn- and Ge- doped ZnTe by first-principles calculations within the DFT+$GW$ formalism. We find that $(\text{Sn}_\text{Zn})$ and $(\text{Ge}_\text{Zn})$ introduce isolated energy levels deep in the band gap of ZnTe, derived from Sn-5s and Ge-4s states, respectively. Moreover, the incorporation of Sn and Ge on the Zn site is favored in p-type ZnTe, in both Zn-rich and Te-rich environments. The optical absorption spectra obtained by solving the Bethe-Salpeter equation reveals that sub-bandgap absorptance is greatly enhanced due to t…
Spin polarization enhancement in a single-layer Bi(1-x)Sb(x) alloy on Ag(111) via isovalent substitution
Centro Atómico Bariloche, CNEA y CONICET（巴里洛切原子中心，国家原子能委员会和阿根廷科学研究委员会）；Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia (CNR-ISM)（意大利国家研究委员会，物质结构研究所）；Instituto de Nanociencia y Nanotecnología (CNEA - CONICET)（纳米科学与纳米技术研究所（国家原子能委员会-阿根廷科学研究委员会））
Synergetic effect of edge states and point defects to tune ferromagnetism in CVD-grown vertical nanostructured MoS2: A correlation between electronic structure and theoretical study
Tuning Optoelectronic Properties and Photoelectrochemical Performance of \b{eta}-TaON via Vanadium Doping
Mads Clausen Institute, University of Southern Denmark（南丹麦大学马兹·克拉斯延研究所）；Department of Materials Science and Engineering, School of Materials and Chemical Technology, Institute of Science Tokyo（东京科学院校材料化学技术学院材料科学与工程系）；Instituto Tecnológico de Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)（查斯科穆斯技术研究所，国家科学技术研究委员会）；Escuela de Bio y Nanotecnologías, Universidad Nacional de San Martín (UNSAM)（圣马丁国立大学生物与纳米技术学院）；Physical−Technical Institute, National Academy of Sciences of Tajikistan（塔吉克斯坦科学院物理技术研究所）；School of Optoelectronic Engineering and CQUPT-BUL Innovation Institute, Chongqing University of Posts and Telecommunications（重庆邮电大学光电工程学院及CQUPT-BUL创新研究院）；Center For Development of Nanotechnology at the National University of Uzbekistan（乌兹别克斯坦国立大学纳米技术开发中心）；Department of Applied Chemistry, School of Science and Technology, Meiji University（明治大学理学院应用化学系）；Institute for Aqua Regeneration, Shinshu University（信州大学水再生研究所）
Graphene functionalization by hydrogen and fluorine has been proposed as a route to modulate its reactivity and electronic properties. However, until now, proposed systems present degradation and limited hydrogen adsorption capacity. In this study, combining first-principles calculations based on density functional theory (DFT) and reactive molecular dynamics, we analyze the tuning of hydrogen adsorption and electronic properties in fluorinated and hydrogenated monolayer graphenes. Our results indicate that fluorine adsorption promotes stronger carbon$-$hydrogen bonds. By changing the concentr…
Site-Selective Yttrium Substitution in Ti3AlC2 Enables Interlayer Engineering and Li Transport in Ti3C2Tx cathodes for High-Power Energy Storage
ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia（瓦伦西亚大学材料科学研究所）；King Danylo University（丹尼洛国王大学）；Department of Applied Physics and Electromagnetism, University of Valencia（瓦伦西亚大学应用物理与电磁学系）
