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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.
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Constructing Tunable Electrides on Monolayer Transition Metal Dichalcogenides
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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- PAR ID:
- 10548391
- Publisher / Repository:
- ACS Publications
- Date Published:
- Journal Name:
- The Journal of Physical Chemistry Letters
- Volume:
- 15
- Issue:
- 23
- ISSN:
- 1948-7185
- Page Range / eLocation ID:
- 6174 to 6182
- Subject(s) / Keyword(s):
- Electrides, Transition metal dichalcogenides, Hydrogen evolution reaction, Density functional calculation
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.jpclett.4c01263
