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Electrides have emerged as promising materials with exotic properties due to the presence of localized electrons detached from all atoms. Despite the continuous discovery of many new electrides, most of them are based on atypical compositions, and their applications require an inert surface structure to passivate reactive excess electrons. Here, we demonstrate a different route to attain tunable electrides. We first report that monolayer transition metal dichalcogenides (TMDCs) exhibit weak electride characteristics, which is the remainder of the electride feature of the transition metal sublattice. By introducing chalcogen vacancies, the enhanced electride characteristics are comparable to those of known electrides. Since the precise tailoring of the chalcogen vacancy concentration has been achieved experimentally, we proposed that TMDCs can be used to build electrides with controllable intensities. Furthermore, we demonstrate that the electride states at the chalcogen vacancy of monolayer TMDCs will play an important role in catalyzing hydrogen evolution reactions.
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Signature of low-dimensional quasi-F centers in zirconium-rich electrides
This work, titled Signature of low-dimensional quasi-F centers in zirconium- rich electrides, presents our newly discovered electride materials amongst zirconium-rich alloys, where non-nuclear interstitial anionic electrons (IAEs), or quasi-F centers, are trapped within the positively charged lattice framework. We utilized quantum mechanical density functional theory (DFT), implemented in the standard Vienna ab initio simulation package (VASP) software program, to investigate the localization of such IAEs within the lattice void spaces. Our electronic-structure calculations confirm the existence and stability of a one-dimensional distribution of localized IAEs interconnected with delocalized electron channels, which is different from other ordinary compounds. Because of their exotic electron-rich properties, electrides have become intriguing materials for a myriad of theoretical and experimental researchers, who seek to understand their unique technological applications in superconductivity, catalytic oxidation, electron emission, reversible hydrogen storage and non-linear optics, and as anode materials in batteries. Indeed, the discovery of electrides is a challenge, and they are still an under-explored class of materials, with only a few electrides being known to date. Herein, we identified novel electride members in Zr2X (X = O, Se, and Te) via several computational insights, which have not been reported yet in the literature.
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- Award ID(s):
- 2004197
- PAR ID:
- 10661256
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Materials Horizons
- Volume:
- 11
- Issue:
- 15
- ISSN:
- 2051-6347
- Page Range / eLocation ID:
- 3613 to 3622
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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The selection and design of charge integration methods remain an outstanding challenge in materials chemistry. In complex materials like electrides, this challenge is amplified by the small charge and complex shape of electride wave functions. For these reasons, popular integration methods, such as the Bader method, usually fail to assign any charge to the bare electrons in an electride. To address this challenge, we developed an algorithm that instead partitions the charge based on the electron localization function (ELF), a popular scheme for visualizing chemically important features in molecules and solids. The algorithm uses Bader segmentation of the ELF to find the electride electrons and Voronoi segmentation of the ELF to identify atoms. We apply this method, “BadELF”, to the quantification of atomic radii and oxidation states in both ionic compounds and electrides. For ionic compounds, we find that the BadELF method yields radii that agree closely with Shannon crystal radii, while the oxidation states agree closely with the Bader method. When they are applied to electrides, however, only the BadELF algorithm yields chemically meaningful charges. We argue that the BadELF method provides a useful strategy to identify electrides and obtain new insight into their most essential property: the quantity of electrons within them.more » « less
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Metal carbides, nitrides, or carbonitrides of early transition metals, better known as MXenes, possess notable structural, electrical, and magnetic properties. Analyzing electronic structures by calculating structural stability, band structure, density of states, Bader charge transfer, and work functions utilizing first principle calculations, we revealed that titanium nitride MXenes, namely TiN and TiN, have excess anionic electrons in their lattice voids, making them MXene electrides. Bulk TiN has competing antiferromagnetic (AFM) and ferromagnetic(FM) configurations with slightly more stable AFM configuration, while the TiN MXene is nonmagnetic. Although TiN favors AFM configuration with hexagonal crystal systems having point group symmetry, TiN does not support altermagnetism. The monolayer of the TiN MXene is a ferromagnetic electride. These unique properties of having non-nuclear interstitial anionic electrons in the electronic structure of titanium nitride MXene have not yet been reported in the literature. Density functional theory calculations show TiN is neither an electride, MXene, or magnetic.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1039/D4MH00437J
