1
|
Cho DY, Kim KJ, Lee KS, Lübben M, Chen S, Valov I. Chemical Influence of Carbon Interface Layers in Metal/Oxide Resistive Switches. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18528-18536. [PMID: 36989142 PMCID: PMC10103050 DOI: 10.1021/acsami.3c00920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Thin layers introduced between a metal electrode and a solid electrolyte can significantly alter the transport of mass and charge at the interfaces and influence the rate of electrode reactions. C films embedded in functional materials can change the chemical properties of the host, thereby altering the functionality of the whole device. Using X-ray spectroscopies, here we demonstrate that the chemical and electronic structures in a representative redox-based resistive switching (RS) system, Ta2O5/Ta, can be tuned by inserting a graphene or ultrathin amorphous C layer. The results of the orbitalwise analyses of synchrotron Ta L3-edge, C K-edge, and O K-edge X-ray absorption spectroscopy showed that the C layers between Ta2O5 and Ta are significantly oxidized to form COx and, at the same time, oxidize the Ta layers with different degrees of oxidation depending on the distance: full oxidation at the nearest 5 nm Ta and partial oxidation in the next 15 nm Ta. The depth-resolved information on the electronic structure for each layer further revealed a significant modification of the band alignments due to C insertion. Full oxidation of the Ta metal near the C interlayer suggests that the oxygen-vacancy-related valence change memory mechanism for the RS can be suppressed, thereby changing the RS functionalities fundamentally. The knowledge on the origin of C-enhanced surfaces can be applied to other metal/oxide interfaces and used for the advanced design of memristive devices.
Collapse
Affiliation(s)
- Deok-Yong Cho
- IPIT
and Department of Physics, Jeonbuk National
University, Jeonju 54896, Republic of Korea
| | - Ki-jeong Kim
- Pohang
Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Kug-Seung Lee
- Pohang
Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Michael Lübben
- Peter
Gruenberg
Institute, Research Centre Juelich, Juelich 52425, Germany
| | - Shaochuan Chen
- IWE2, RWTH Aachen University, Sommerfed strasse 24, Aachen 52074, Germany
| | - Ilia Valov
- Peter
Gruenberg
Institute, Research Centre Juelich, Juelich 52425, Germany
- Institute
of Electrochemistry and Energy Systems “acad. E. Budewski”, Bulgarian Academy of Sciences, “acad. G Bonchev” street Bl.10, Sofia 1113, Bulgaria
| |
Collapse
|
2
|
Perrella F, Coppola F, Rega N, Petrone A. An Expedited Route to Optical and Electronic Properties at Finite Temperature via Unsupervised Learning. Molecules 2023; 28:molecules28083411. [PMID: 37110644 PMCID: PMC10144358 DOI: 10.3390/molecules28083411] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 04/06/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
Electronic properties and absorption spectra are the grounds to investigate molecular electronic states and their interactions with the environment. Modeling and computations are required for the molecular understanding and design strategies of photo-active materials and sensors. However, the interpretation of such properties demands expensive computations and dealing with the interplay of electronic excited states with the conformational freedom of the chromophores in complex matrices (i.e., solvents, biomolecules, crystals) at finite temperature. Computational protocols combining time dependent density functional theory and ab initio molecular dynamics (MD) have become very powerful in this field, although they require still a large number of computations for a detailed reproduction of electronic properties, such as band shapes. Besides the ongoing research in more traditional computational chemistry fields, data analysis and machine learning methods have been increasingly employed as complementary approaches for efficient data exploration, prediction and model development, starting from the data resulting from MD simulations and electronic structure calculations. In this work, dataset reduction capabilities by unsupervised clustering techniques applied to MD trajectories are proposed and tested for the ab initio modeling of electronic absorption spectra of two challenging case studies: a non-covalent charge-transfer dimer and a ruthenium complex in solution at room temperature. The K-medoids clustering technique is applied and is proven to be able to reduce by ∼100 times the total cost of excited state calculations on an MD sampling with no loss in the accuracy and it also provides an easier understanding of the representative structures (medoids) to be analyzed on the molecular scale.
Collapse
Affiliation(s)
- Fulvio Perrella
- Scuola Superiore Meridionale, Largo San Marcellino 10, I-80138 Napoli, Italy
| | - Federico Coppola
- Scuola Superiore Meridionale, Largo San Marcellino 10, I-80138 Napoli, Italy
| | - Nadia Rega
- Scuola Superiore Meridionale, Largo San Marcellino 10, I-80138 Napoli, Italy
- Department of Chemical Sciences, University of Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia 21, I-80126 Napoli, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Universitario di M.S. Angelo ed. 6, via Cintia 21, I-80126 Napoli, Italy
| | - Alessio Petrone
- Scuola Superiore Meridionale, Largo San Marcellino 10, I-80138 Napoli, Italy
- Department of Chemical Sciences, University of Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia 21, I-80126 Napoli, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Universitario di M.S. Angelo ed. 6, via Cintia 21, I-80126 Napoli, Italy
| |
Collapse
|
3
|
Nascimento DR, Govind N. Computational approaches for XANES, VtC-XES, and RIXS using linear-response time-dependent density functional theory based methods. Phys Chem Chem Phys 2022; 24:14680-14691. [PMID: 35699090 DOI: 10.1039/d2cp01132h] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The emergence of state-of-the-art X-ray light sources has paved the way for novel spectroscopies that take advantage of their atomic specificity to shed light on fundamental physical, chemical, and biological processes both in the static and time domains. The success of these experiments hinges on the ability to interpret and predict core-level spectra, which has opened avenues for theory to play a key role. Over the last two decades, linear-response time-dependent density functional theory (LR-TDDFT), despite various theoretical challenges, has become a computationally attractive and versatile framework to study excited-state spectra including X-ray spectroscopies. In this context, we focus our discussion on LR-TDDFT approaches for the computation of X-ray Near-Edge Structure (XANES), Valence-to-Core X-ray Emission (VtC-XES), and Resonant Inelastic X-ray Scattering (RIXS) spectroscopies in molecular systems with an emphasis on Gaussian basis set implementations. We illustrate these approaches with applications and provide a brief outlook of possible new directions.
Collapse
Affiliation(s)
- Daniel R Nascimento
- Department of Chemistry, The University of Memphis, Memphis, TN, 38152, USA.
| | - Niranjan Govind
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
| |
Collapse
|
4
|
Khalili F, Vafaee M, Shokri B. Attosecond charge migration following oxygen K-shell ionization in DNA bases and base pairs. Phys Chem Chem Phys 2021; 23:23005-23013. [PMID: 34611693 DOI: 10.1039/d1cp02920g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Core ionization of DNA begins a cascade of events which could lead to cellular inactivation or death. The created core-hole following an impulse inner-shell ionization of molecules naturally decays in the auger timescale. We simulated charge migration (CM) phenomena following an impulsive core ionization of individual DNA bases at the oxygen K-edge which occurs before Auger decay of the oxygen. Our approach is based on real-time time dependent density functional theory (RT-TDDFT). It is shown that the pronounced hole fluctuation observed around bonds of the initial core-hole results in various valence orbital migrations. Also, the same photo-core-ionized dynamics is studied for the related base pairs. We investigate the role of base pairing and H-bonding interactions in the attosecond CM dynamics. In particular, the creation of a core-hole in the oxygen involved in H-bonding leads to an enhancement of charge migration relative to the respective single bases. Importantly, the hole oscillation of the adenine-thymine base pair upon creation of a core-hole at the oxygen, which does not contribute to the donor-acceptor interactions (not H-bonded), decreases compared to the single thymine base. Understanding the detailed dynamics of the localized core-hole initiating CM process would open the way for chemically controlling DNA damage/repair in the future.
Collapse
Affiliation(s)
- Fatemeh Khalili
- Department of Physics, Shahid Beheshti University, Velenjak, Tehran 19839, Iran.
| | - Mohsen Vafaee
- Department of Chemistry, Tarbiat Modares University, P. O. Box 14115-175, Tehran, Iran.
| | - Babak Shokri
- Department of Physics, Shahid Beheshti University, Velenjak, Tehran 19839, Iran. .,Laser-Plasma Research Institute, Shahid Beheshti University, Velenjak, Tehran 19839, Iran
| |
Collapse
|
5
|
Loe CM, Liekhus-Schmaltz C, Govind N, Khalil M. Spectral Signatures of Ultrafast Excited-State Intramolecular Proton Transfer from Computational Multi-edge Transient X-ray Absorption Spectroscopy. J Phys Chem Lett 2021; 12:9840-9847. [PMID: 34606267 DOI: 10.1021/acs.jpclett.1c02483] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Excited-state intramolecular proton transfer (ESIPT) is a fundamental chemical process with several applications. Ultrafast ESIPT involves coupled electronic and atomic motions and has been primarily studied using femtosecond optical spectroscopy. X-ray spectroscopy is particularly useful because it is element-specific and enables direct, individual probes of the proton-donating and -accepting atoms. Herein, we report a computational study to resolve the ESIPT in 10-hydroxybenzo[h]quinoline (HBQ), an intramolecularly hydrogen bonded compound. We use linear-response time-dependent density functional theory (LR-TDDFT) combined with ab initio molecular dynamics (AIMD) and time-resolved X-ray absorption spectroscopy (XAS) computations to track the ultrafast excited-state dynamics. Our results reveal clear X-ray spectral signatures of coupled electronic and atomic motions during and following ESIPT at the oxygen and nitrogen K-edge, paving the way for future experiments at X-ray free electron lasers.
Collapse
Affiliation(s)
- Caroline M Loe
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | | | - Niranjan Govind
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Munira Khalil
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| |
Collapse
|
6
|
Li X, Govind N, Isborn C, DePrince AE, Lopata K. Real-Time Time-Dependent Electronic Structure Theory. Chem Rev 2020; 120:9951-9993. [DOI: 10.1021/acs.chemrev.0c00223] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Niranjan Govind
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Christine Isborn
- Department of Chemistry and Chemical Biology, University of California, Merced, California 95343, United States
| | - A. Eugene DePrince
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Kenneth Lopata
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| |
Collapse
|
7
|
Chen M, Lopata K. First-Principles Simulations of X-ray Transient Absorption for Probing Attosecond Electron Dynamics. J Chem Theory Comput 2020; 16:4470-4478. [PMID: 32470295 PMCID: PMC7467644 DOI: 10.1021/acs.jctc.0c00122] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
X-ray transient absorption spectroscopy (XTAS) is a promising technique for measuring electron dynamics in molecules and solids with attosecond time resolutions. In XTAS, the elemental specificity and spatial locality of core-to-valence X-ray absorption is exploited to relate modulations in the time-resolved absorption spectra to local electron density variations around particular atoms. However, interpreting these absorption modulations and frequency shifts as a function of the time delay in terms of dynamics can be challenging. In this paper, we present a first-principles study of attosecond XTAS in a selection of simple molecules based on real-time time-dependent density functional theory (RT-TDDFT) with constrained DFT to emulate the state of the system following the interaction with a ultraviolet pump laser. In general, there is a decrease in the optical density and a blue shift in the frequency with increasing electron density around the absorbing atom. In carbon monoxide (CO), modulations in the O K-edge occur at the frequency of the valence electron dynamics, while for dioxygen (O2) they occur at twice the frequency, due to the indistinguishability of the oxygen atoms. In 4-aminophenol (H2NC6H4OH), likewise, there is a decrease in the optical density and a blue shift in the frequency for the oxygen and nitrogen K-edges with increasing charge density on the O and N, respectively. Similar effects are observed in the nitrogen K-edge for a long-range charge-transfer excitation in a benzene (C6H6)-tetracyanoethylene (C6N4; TCNE) dimer but with weaker modulations due to the delocalization of the charge across the entire TCNE molecule. Additionally, in all cases, there are pre-edge features corresponding to core transitions to depopulated orbitals. These potentially offer a background-free signal that only appears in pumped molecules.
Collapse
Affiliation(s)
- Min Chen
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Kenneth Lopata
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| |
Collapse
|
8
|
Zheng X, Liu J, Doumy G, Young L, Cheng L. Hetero-site Double Core Ionization Energies with Sub-electronvolt Accuracy from Delta-Coupled-Cluster Calculations. J Phys Chem A 2020; 124:4413-4426. [DOI: 10.1021/acs.jpca.0c00901] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xuechen Zheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Junzi Liu
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Gilles Doumy
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Linda Young
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| |
Collapse
|