Ternary inorganic electrides with mixed bonding

Abstract

A high-throughput screening based on first-principles calculations was performed to search for new ternary inorganic electrides. From the available materials database, we identified three new thermodynamically stable materials (Li12Mg3Si4, NaBa2O and Ca5Ga2N4) as potential electrides made by main group elements, in addition to the well known mayenite based electride (C12A7:e − ). Different from those conventional inorganic electrides in which the excess electrons play only the role of anions, the three new materials, resembling the electrides found in simple metals under high pressure, possess mixed ionic and metallic bonding. The interplay between two competing mechanisms, together with the different crystal packing motifs, gives rise to a variety of geometries in anionic electrons, and rich physical phenomena such as ferromagnetism, superconductivity and metal-insulator transition. Our finding here bridges the gap between electrides found at ambient and high pressure conditions.

Formation mechanism of chemically precompressed hydrogen clathrates in metal superhydrides

“…S3 and S4 in the Supplemental Material), showing that the electridelike characteristics of metal frameworks are enhanced with in-creasing pressure. Indeed, the localization of interstitial excess electrons also emerges in compressed alkali metals at high pressures [52][53][54], in order to reduce Coulomb repulsions arising from the overlap of atomic valence electrons. Such loosely bound anionic electrons residing in the metal frameworks of compressed superhydrides can be easily captured to H atoms, forming H cages with attractive Coulomb interactions between cationic metal and anionic H atoms.…”

Floating Interlayer and Surface Electrons in 2D Materials: Graphite, Electrides, and Electrenes

“…The contribution of Y to the magnetization density, estimated from the ionic radius of 0.9 Å for Y 3+ , accounts for only 7.1% of the total magnetization, implying that the ferromagnetism is induced by the anionic nonnuclear electrons. Such Stoner‐type ferromagnetism originating from the spin polarization of anionic electrons has been predicted to occur in YCl, [ 62 ] LaBr 2 , [ 63 ] La 2 Br 5 , [ 63 ] and Ca 5 Ga 2 N 4 [ 64 ] at ambient pressure and in alkali metals under ultrahigh pressures. [ 65 ]…”

“…The comprehensive screening of material databases for electrides has been conducted recently by two groups, [ 33,34 ] which reported a large number of Q2DEs (PrGa, CaAu, NdGa, CaSi, SrSn, BaGe, SrGe, CaGe, SrSi, LaRuSi, [ 78 ] PrScGe, NdScGe, SmScSi, BaSn, HoMgSn, PrScGe, NdScGe, TbMgSn, LaScGe, TmMgSn, ErMgSn, PrScSi, SmTiGe, NdScSi, CeScSb, YTiGe, Pr 2 MgNi 2 , Pr 2 MgGe 2 , Nd 2 MgNi 2 , Sm 2 MgGe 2 , Dy 2 MgSi 2 , Ce 2 MgSi 2 , Dy 2 MgGe 2 , Mg(ScGa) 2 , Tb 2 MgNi 2 , Y 2 MgCu 2 , Li(NdSi) 2 , Yb 2 MgSi 2 , Mg 3 Sn, Pr 5 (CoB 3 ) 2 , Nd 5 (CoB 3 ) 2 , Ba 2 LiN,Na 3 Cl 2 , Ca 5 Ga 2 N 4 [ 64 ] ). A more detailed account of their electronic structures is warranted.…”

Gapped metals as thermoelectric materials revealed by high-throughput screening

“…Li 12 Mg 3 Si 4 and Ca 3 CrN 3 have been identified as potential electrides in Refs. [104] and [38], respectively. However, since these classes of materials are usually less stable at high temperatures, they might not be suitable for TE applications.…”