scholarly journals Atomic-Scale Observation of Spontaneous Hole Doping and Concomitant Lattice Instabilities in Strained Nickelate Films

2022 ◽  
Author(s):  
I. C. Lin ◽  
M. H. Lee ◽  
P. C. Wu ◽  
S. C. Lin ◽  
J. W. Chen ◽  
...  
Keyword(s):  
Atomic Scale ◽  
Hole Doping ◽  
Ionic Radii ◽  
Emergent Phenomena ◽  
Epitaxial Strain ◽  
Charge Doping ◽  
Thin Oxide Films ◽  
Band Alignments ◽  
Hidden Orders ◽  
Interfacial Charge

Abstract Thin oxide films are of vast opportunities for modern electronics and can facilitate emergent phenomena by factors absent in the bulk counterparts, such as the ubiquitous epitaxial strain and interfacial charge doping. Here, we demonstrate the twisting of intended bulk-metallic phases in 10-unit-cell LaNiO3, PrNiO3, and NdNiO3 films on (001)-oriented SrTiO3 into distinct charge-lattice entangled states by epitaxial strains. Using atomically-resolved electron microscopy and spectroscopy, the interfacial electron doping into SrTiO3 in the conventional context of band alignments are discounted. Instead, spontaneously doped holes that are localized and at the order of 1013 cm-2 are atomically unraveled across all three heterointerfaces and associated with strain mitigations by the accompanied atomic intermixing with various ionic radii. The epitaxial strains also lead to condensations of monoclinic-C2/c lattice instabilities, which are hidden to the bulk phase diagram. The group-theoretical analysis of characteristic transition pathways unveils the strain resurrection of the hidden C2/c symmetry. While this strain-induced monoclinic phase in LaNiO3 remains metallic at room temperature, those in PrNiO3 and NdNiO3 turn out to be insulating. Such strain-induced monoclinic lattice instabilities and parasitic localized holes go beyond the classical elastic deformations of films upon epitaxial strains and hint on plausible hidden orders in versatile oxide heterostructures with unexpected properties, of which the exploration is only at the infancy and full of potentials.

scholarly journals Charge-induced electromechanical actuation of Mo- and W-dichalcogenide monolayers

RSC Advances ◽  
2018 ◽  
Vol 8 (67) ◽  
pp. 38667-38672 ◽  
Author(s):  
Vuong Van Thanh ◽  
Nguyen Tuan Hung ◽  
Do Van Truong
Keyword(s):  
Density Functional Calculations ◽  
Density Functional ◽  
Hole Doping ◽  
First Principle ◽  
Two Dimensional ◽  
Electromechanical Properties ◽  
Charge Doping ◽  
Electromechanical Actuation

Using first-principle density functional calculations, we investigate electromechanical properties of two-dimensional MX2 (M = Mo, W; X = S, Se, Te) monolayers with the 1H and 1T structures as a function of charge doping for both electron and hole doping.

Facile interfacial charge transfer across hole doped cobalt-based MOFs/TiO2 nano-hybrids making MOFs light harvesting active layers in solar cells

2015 ◽  
Vol 3 (45) ◽  
pp. 22669-22676 ◽  
Author(s):  
Deok Yeon Lee ◽  
Iseul Lim ◽  
Chan Yong Shin ◽  
Supriya A. Patil ◽  
Wonjoo Lee ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Solar Radiation ◽  
Light Harvesting ◽  
Hole Doping ◽  
Interfacial Charge Transfer ◽  
Active Layers ◽  
Interfacial Charge

Hole doping leads to an efficient photo-induced interfacial charge transfer from MOFs to TiO2 and thereby the MOFs can harvest solar radiation to generate electricity.

scholarly journals Modeling Superconducting Critical Temperature of 122-Iron-Based Pnictide Intermetallic Superconductor Using a Hybrid Intelligent Computational Method

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4604
Author(s):  
Oluwatobi Akomolafe ◽  
Taoreed O. Owolabi ◽  
Mohd Amiruddin Abd Rahman ◽  
Mohd Mustafa Awang Kechik ◽  
Mohd Najib Mohd Yasin ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Structural Transformation ◽  
Mean Absolute Error ◽  
Low Cost ◽  
Absolute Error ◽  
Computational Method ◽  
Hole Doping ◽  
Support Vector ◽  
Ionic Radii ◽  
Iron Based

Structural transformation and magnetic ordering interplays for emergence as well as suppression of superconductivity in 122-iron-based superconducting materials. Electron and hole doping play a vital role in structural transition and magnetism suppression and ultimately enhance the room pressure superconducting critical temperature of the compound. This work models the superconducting critical temperature of 122-iron-based superconductor using tetragonal to orthorhombic lattice (LAT) structural transformation during low-temperature cooling and ionic radii of the dopants as descriptors through hybridization of support vector regression (SVR) intelligent algorithm with particle swarm (PS) parameter optimization method. The developed PS-SVR-RAD model, which utilizes ionic radii (RAD) and the concentrations of dopants as descriptors, shows better performance over the developed PS-SVR-LAT model that employs lattice parameters emanated from structural transformation as descriptors. Using the root mean square error (RMSE), coefficient of correlation (CC) and mean absolute error as performance measuring criteria, the developed PS-SVR-RAD model performs better than the PS-SVR-LAT model with performance improvement of 15.28, 7.62 and 72.12%, on the basis of RMSE, CC and Mean Absolute Error (MAE), respectively. Among the merits of the developed PS-SVR-RAD model over the PS-SVR-LAT model is the possibility of electrons and holes doping from four different dopants, better performance and ease of model development at relatively low cost since the descriptors are easily fetched ionic radii. The developed intelligent models in this work would definitely facilitate quick and precise determination of critical transition temperature of 122-iron-based superconductor for desired applications at low cost with experimental stress circumvention.

scholarly journals Redox-governed charge doping dictated by interfacial diffusion in two-dimensional materials

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Kwanghee Park ◽  
Haneul Kang ◽  
Seonghyun Koo ◽  
DaeEung Lee ◽  
Sunmin Ryu
Keyword(s):  
Molecular Diffusion ◽  
Charge Carriers ◽  
Hole Doping ◽  
Water Molecules ◽  
Two Dimensional ◽  
Nernst Equation ◽  
Redox Couples ◽  
Extra Charge ◽  
Two Dimensional Materials ◽  
Charge Doping

Abstract Controlling extra charge carriers is pivotal in manipulating electronic, optical, and magnetic properties of various two-dimensional materials. Nonetheless, the ubiquitous hole doping of two-dimensional materials in the air and acids has been controversial in its mechanistic details. Here we show their common origin is an electrochemical reaction driven by redox couples of oxygen and water molecules. Using real-time photoluminescence imaging of WS2 and Raman spectroscopy of graphene, we capture molecular diffusion through the two-dimensional nanoscopic space between two-dimensional materials and hydrophilic substrates, and show that the latter accommodate water molecules also serving as a hydrating solvent. We also demonstrate that HCl-induced doping is governed by dissolved O2 and pH in accordance with the Nernst equation. The nanoscopic electrochemistry anatomized in this work sets an ambient limit to material properties, which is universal to not only 2D but also other forms of materials.

scholarly journals Heteroepitaxial vertical perovskite hot-electron transistors down to the monolayer limit

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Brian S. Y. Kim ◽  
Yasuyuki Hikita ◽  
Takeaki Yajima ◽  
Harold Y. Hwang
Keyword(s):  
Mean Free Path ◽  
Water Soluble ◽  
Atomic Scale ◽  
Hot Electron ◽  
Hot Carrier ◽  
Emergent Phenomena ◽  
Hot Electron Injection ◽  
Electronic Probe ◽  
Electron Mean Free Path ◽  
Electron Transistors

AbstractTwo-dimensional heterostructures combined with vertical geometries are candidates to probe and utilize the physical properties of atomically-thin materials. The vertical configuration enables a unique form of hot-carrier spectroscopy as well as atomic-scale devices. Here, we present the room-temperature evolution of heteroepitaxial perovskite hot-electron transistors using a SrRuO3 base down to the monolayer limit (∼4 Å). As a fundamental electronic probe, we observe an abrupt transition in the hot-electron mean free path as a function of base thickness, coinciding with the thickness-dependent resistive transition. As a path towards devices, we demonstrate the integrated synthesis of perovskite one-dimensional electrical edge contacts using water-soluble and growth-compatible Sr3Al2O6 hard masks. Edge-contacted monolayer-base transistors exhibit on/off ratios reaching ∼108, complete electrostatic screening by the base manifesting pure hot-electron injection, and excellent scaling of the output current density with device dimensions. These results open new avenues for incorporating emergent phenomena at oxide interfaces and in heterostructures.

scholarly journals Direct Vapor Growth of 2D Vertical Heterostructures with Tunable Band Alignments and Interfacial Charge Transfer Behaviors

2019 ◽  
Vol 6 (7) ◽  
pp. 1802204 ◽  
Author(s):  
Weihao Zheng ◽  
Biyuan Zheng ◽  
Changlin Yan ◽  
Ying Liu ◽  
Xingxia Sun ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Interfacial Charge Transfer ◽  
Vapor Growth ◽  
Band Alignments ◽  
Interfacial Charge

Photovoltaic modulation of ferromagnetism within a FM metal/P–N junction Si heterostructure

Nanoscale ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 272-279
Author(s):  
Yifan Zhao ◽  
Shishun Zhao ◽  
Lei Wang ◽  
Shiping Wang ◽  
Yujing Du ◽  
...  
Keyword(s):  
Spintronic Device ◽  
Charge Doping ◽  
Interfacial Charge ◽  
Si Wafer

A prototype photovoltaic spintronic device with a p–n junction Si wafer is proposed, which generates photo-induced electrons and changes the ferromagnetism of Co or CoFeB by interfacial charge doping.

scholarly journals Epitaxial antiperovskite/perovskite heterostructures for materials design

2020 ◽  
Vol 6 (30) ◽  
pp. eaba4017
Author(s):  
Camilo X. Quintela ◽  
Kyung Song ◽  
Ding-Fu Shao ◽  
Lin Xie ◽  
Tianxiang Nan ◽  
...  
Keyword(s):  
Complex Oxide ◽  
Materials Design ◽  
Atomic Scale ◽  
Spectroscopic Techniques ◽  
First Principles Calculations ◽  
Emergent Phenomena ◽  
Perovskite Materials ◽  
Resolution Imaging ◽  
Oxide Perovskite ◽  
Sharp Interfaces

Engineered heterostructures formed by complex oxide materials are a rich source of emergent phenomena and technological applications. In the quest for new functionality, a vastly unexplored avenue is interfacing oxide perovskites with materials having dissimilar crystallochemical properties. Here, we propose a unique class of heterointerfaces based on nitride antiperovskite and oxide perovskite materials as a previously unidentified direction for materials design. We demonstrate the fabrication of atomically sharp interfaces between nitride antiperovskite Mn3GaN and oxide perovskites (La0.3Sr0.7)(Al0.65Ta0.35)O3 and SrTiO3. Using atomic-resolution imaging/spectroscopic techniques and first-principles calculations, we determine the atomic-scale structure, composition, and bonding at the interface. The epitaxial antiperovskite/perovskite heterointerface is mediated by a coherent interfacial monolayer that interpolates between the two antistructures. We anticipate our results to be an important step for the development of functional antiperovskite/perovskite heterostructures, combining their unique characteristics such as topological properties for ultralow-power applications.

scholarly journals Tunable Rashba spin splitting in Janus transition-metal dichalcogenide monolayers via charge doping

RSC Advances ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 6388-6394
Author(s):  
Jiajia Chen ◽  
Kai Wu ◽  
Huanhuan Ma ◽  
Wei Hu ◽  
Jinlong Yang
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Spin Splitting ◽  
Hole Doping ◽  
Transition Metal Dichalcogenide ◽  
Rashba Effect ◽  
Rashba Spin ◽  
Rashba Spin Splitting ◽  
Charge Doping ◽  
Metal Dichalcogenides

Two-dimensional Janus transition-metal dichalcogenides possess an intrinsic Rashba effect, which can be manipulated by charge doping. Electron doping can effectively strengthen the Rashba effect, while hole doping would weaken it.

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