New Kagome Metal Sc₃Mn₃Al₇Si₅ and Its Gallium-Doped Analogues: Synthesis, Crystal Structure, and Physical Properties

Abstract

We report the synthesis, crystal structure, and basic properties of the new intermetallic compound Sc3Mn3Al7Si5. The structure of the compound was established by single-crystal X-ray diffraction, and it crystallizes with a hexagonal structure (Sc3Ni11Si4 type) with Mn atoms forming the Kagome nets. The dc magnetic susceptibility measurements reveal a Curie-Weiss moment of ~0.51 μ(B)/Mn; however, no magnetic order is found for temperatures as low as 1.8 K. Electrical resistivity and heat capacity measurements show that this compound is definitively metallic, with a relatively large specific heat Sommerfeld coefficient, indicating strong electronic correlations. Intriguingly, these features have revealed Sc3Mn3Al7Si5 as a possible quantum spin liquid. With chemical and lattice disorder introduced by doping, a spin liquid to spin glass transition is observed in the highest Ga-doped compounds. The roles of the geometrically frustrated structure and Mn-ligand hybridization in the magnetism of the title compounds are also discussed.

Synthesis and Characterization of Bournonite PbCuSbS3 Nanocrystals

“…[22,23] From this fit we obtain γ = 10.9 mJ mol -1 K -2 and β = 3.0 mJ mol -1 K -4 , values that are relatively high compared with that of metals and lower than that of oxides and other wide band gap semiconductors. [24][25][26] From the low temperature C p data an estimation of the Density of States (DOS) at the Fermi Level, N(E F ), can be obtained by using the relation [22,27] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 where λ e-ph is the electron-phonon coupling constant. Setting λ e-ph to zero as a first approximation N(E F ) = 4.6 states eV -1 per formula unit.…”

Physical properties of madocite: A quaternary chalcogenide with very low thermal conductivity

“…[16,17] From this fit we obtain  = 361 mJ mol -1 K -2 and  = 51 mJ mol -1 K -4 , values that are relatively high compared with that of metals but lower than that of oxides and other wide band gap semiconductors. [18][19][20] Using the relation 13 4 12 5…”

Intermediate valence in single crystallineYb2Si2Al

“…For Yb 52 final state effects are much smaller than, for example Ce so that we omit an Anderson impurity model in the formalism 53 of Gunnarson and Schönhammer. 54 Instead we assume that the f 13…”

“…The methods are based on the presence of a core hole that acts differently on the two valence configurations that form the intermediate valent ground state (c 13 f 13 + c 14 f 14 ). Accordingly, spectral features (cf 13 and cf 14 L with c representing a core hole) appear in the XAS or PES spectra. The intensities I(cf 13 ) and I(cf 14 L) (referred to as I(f 13 ) and I(f 14 ) for simplicity) of these structures can be related to the weights (c 2 13 , c 2 14 ) of the f states in the initial state.…”

“…Perhaps the earliest report of such a system was the allotrope β-Mn, which has a pyrochlore structure 11,12 , and there is a more recent report of Sc 3 Mn 3 Al 7 Si 5 , where Mn moments lie on a Kagome lattice. 13 There is an increasing number of systems where rare earth moments lie on geometrically frustrated lattices, such as pyrochlore Pr 2 Ir 2 O 7 , 14 and the Kagome lattice systems CePdAl 15,16 and YbAgGe. 17 We will focus here on a different frustrated lattice, where rare earth moments form planes of orthogonal dimers in the Shastry-Sutherland Lattice (SSL).…”