Semimetallic bands derived from interlayer electrons in the quasi-two-dimensional electride 
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Horiba, Koji; Yukawa, Ryu; Mitsuhashi, T.; Kitamura, Miho; Inoshita, Takeshi; Hamada, Nobuyuki; Otani, Shigeki; Ohashi, Naoki; Maki, Sachiko; Yamaura, Jun Ichi; Hosono, Hideo; Murakami, Youichi; Kumigashira, Hiroshi

doi:10.1103/physrevb.96.045101

Cited by 19 publications

(24 citation statements)

References 34 publications

(44 reference statements)

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“…Since the first demonstration of Ca 2 N as a Q2D electride, [3] studies on the magnetic, [5,7,8,9,10,11] optical, [12] and mechanical [13] properties of layered electrides have been reported. Angle-resolved photoemission spectroscopy (ARPES) measurements have successfully identified the Q2D anionic bands of Ca 2 N [14] and Y 2 C, [15] which are in excellent agreement with those predicted by ab initio calculations based on density functional theory (DFT). The surface electronic structures of layered electrides have been calculated recently: it was revealed that they possess an extra-surface state, i.e., a two-dimensional (2D) free-electron-like state with the electrons literally floating outside the surface.…”

Section: Introductionsupporting

confidence: 60%

Probing a divergent van Hove singularity of graphene with a Ca2N support: A layered electride as a solid-state dopant

et al. 2017

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Layered electrides, as typified by Ca 2 N, are a new class of quasitwo-dimensional materials with low work functions. Using first-principles calculations, we have shown that a graphene layer deposited on Ca 2 N is doped to n = 5×10 14 cm −2 with its Fermi level aligned with the logarithmically divergent van Hove singularity in the graphene π * band. For bilayer graphene on Ca 2 N, the inner graphene layer is doped to the same level, while the doping of the outer graphene layer is much more modest. This finding opens an interesting possibility of using layered electrides for the exploration of van Hove physics. The work function changes nonmonotonically with the number of graphene layers, which we explain in terms of the peculiar electronic structures of the constituent materials and their bonding. arXiv:1708.01048v1 [cond-mat.mtrl-sci]

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Section: Introductionsupporting

confidence: 60%

Probing a divergent van Hove singularity of graphene with a Ca2N support: A layered electride as a solid-state dopant

et al. 2017

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“…We have also tried the patterning procedure by using Ag or Cu instead of Au, which leads to a similar effect but with weaker SOC. The discovery of more and more new electride materials holding anionic electrons [50,51], especially the experimentally synthesized layered electrides such as Y 2 C [45,52], provides a unique material platform to achieve the novel patterning procedure. The emergent 2D molecular crystals and metal-organic frameworks can serve as another category of candidates to materialize the proposed CT lattice model.…”

Section: E E H K T E E T E E T E E T E Ementioning

confidence: 99%

Kagome bands disguised in a coloring-triangle lattice

et al. 2019

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The Kagome bands hosting exotic quantum phases are generally and understandably pertained only to a Kagome lattice. This has severely hampered the research of Kagome physics due to the lack of real Kagome-lattice materials.Interestingly we discover that a coloring-triangle (CT) lattice, named after color-triangle tiling, hosts also Kagome bands. We demonstrate first theoretically the equivalency between the Kagome and CT lattice, and then computationally in photonic (waveguide lattice) and electronic (Au overlayer on electride Ca 2 N surface) systems by respective finite-element and first-principles calculations. The theory can be generalized to even distorted Kagome and CT lattices to exhibit ideal Kagome bands. Our findings open a new avenue to explore the alluding Kagome physics.

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“…The DFT calculation has shown that ferromagnetic instability (Stoner type) in Y 2 C is indeed suppressed when considering the onsite Coulomb energy (U) for the 4d orbital [18]. Therefore, the absence of magnetic order as well as the appearance of localized moments at the Y site in the pc sample strongly suggest the importance of electron correlation in gaining a detailed understanding of the electronic ground state in Y 2 C. In fact, ARPES experiments have shown that the observed band structure is better described by DFT calculation where U for the 4d orbital [19] is taken into account. How- ever, we note that our result does not necessarily disfavor the recently suggested scenario that attributes the discrepancy between ARPES and DFT to the surface state stemming from "topological" nature of the electride band [28].…”

mentioning

confidence: 99%

“…1(a)] belongs to the space group R 3m with the lattice constant for the a (c)-axis being 3.6164 (17.9651) Å for Y 2 C. A DFT calculation suggests 2D elec-tride features similar to Ca 2 N [17] for this compound, where the electron band near the Fermi energy consists of Y 4d orbitals and the 2D electronic states are present between the Y layers. While these predicted band structures [14,17,18] have been confirmed by angle-resolved photoemission spectroscopy (ARPES) [15,19], the interesting possibility of ferromagnetic instability associated with electride bands, which has been suggested for Y 2 C [18] is yet to be observed experimentally.…”

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confidence: 99%

Electronic correlation in the quasi-two-dimensional electride Y2C

et al. 2018

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Magnetic properties of the electride compound Y 2 C were investigated by muon spin rotation and magnetic susceptibility on two samples with different form (poly-and single-crystalline), to examine the theoreticallypredicted Stoner ferromagnetism for the electride bands. There was no evidence of static magnetic order in both samples even at temperatures down to 0.024 K. For the poly-crystalline sample, the presence of a paramagnetic moment at Y sites was inferred from the Curie-Weiss behavior of the muon Knight shift and susceptibility, whereas no such tendency was observed in the single-crystalline sample. These observations suggest that the electronic ground state of Y 2 C is at the limit between weak-to-strong electronic correlation, where onsite Coulomb repulsion is sensitive to a local modulation of the electronic state or a shift in the Fermi level due to the presence of defects/impurities.Electrides are a class of materials in which electrons serve as anions (without atomic nuclei) in the positively charged lattice framework sustained by covalent bonds [1,2]. In view of their promising properties such as high electrical conductivity, low work function, and significant catalytic activity in their ideal form, electrides are drawing much attention from the research community. However, most of the reported electrides are not stable under ambient atmosphere [2,3], which leads to the difficulty in the development of possible applications. The first non-aerophobic electride compound that paved the way to various applications was mayenite, [Ca 24 Al 28 O 64 ] 4+ 4e − (C12A7:e − ), which was reported in 2003 by Matsuishi et al.[4]. Mayenite has positively charged nano-sized Ca-Al-O cages and endohedral electrons that maintain charge neutrality of the unit cell. The electrons at the cage center move to an empty neighboring cage by quantum tunneling, thus contributing to the high electric conductivity. Despite its low work function (∼2.4 eV, comparable to that of alkali-metals), C12A7:e − is stable in ambient environment [5] and can therefore be used in a wide range of applications [6][7][8][9][10][11][12].Recently, a layered nitride compound with the formula Ca 2 N was reported to be an electride [13,14], in which, based on bulk property measurements as well as on a recent ARPES study in combination with density functional theory (DFT), it was proposed that electrons were extended in two-dimension (2D) over the interlameller space between the calcium layers [15]. Since the dimensionality of the anion electrons plays an important role in determining the bulk electronic properties of the material, 2D electrides are currently under spotlight in materials science research.Yttrium carbide Y 2 C is one such compound, which has attracted much attention in recent time, as it is isostructural to Ca 2 N [16,17]. The lattice structure of these two compounds [shown in Fig. 1(a)] belongs to the space group R3m with the lattice constant for the a (c)-axis being 3.6164 (17.9651) Å for Y 2 C. A DFT calculation suggests 2D elec-tride...

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Semimetallic bands derived from interlayer electrons in the quasi-two-dimensional electride Y2C

Cited by 19 publications

References 34 publications

Probing a divergent van Hove singularity of graphene with a Ca2N support: A layered electride as a solid-state dopant

Probing a divergent van Hove singularity of graphene with a Ca2N support: A layered electride as a solid-state dopant

Kagome bands disguised in a coloring-triangle lattice

Electronic correlation in the quasi-two-dimensional electride Y2C

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