A. CZYBULKA's research while affiliated with University of Cologne and other places

... Another type-I clathrate with Tt = Ge and T = Zn (besides K 8 Zn x Ge 46-x [16] mentioned above) is Ba 8 Zn 8 Ge 38 . [26] Na atoms in guest positions are less frequent but are found in Rb 6 Na 2 Ge 44.89 , Cs 6 Na 2 Zn 4 Ge 42 and Cs 6.40 Na 1.60 Ga 8 Ge 38 , [27] as well as in Na 8 Tr x Ge 46-x with Tr = Al and Ga. [28] Notably, a binary A 8 Ge 46-y ᮀ y phase with A = Na has not been reported, and Na is generally considered not to fit well in the larger cages of a Ge type-I clathrate host framework. ...

... Large areas of the Earth are exposed to concentrations of tropospheric ozone (O 3 ) that exceed levels known to be toxic to plants 4,6 . In addition to reducing plant growth, exposure to elevated O 3 can also alter plant tissue chemistry 7 and reduce allocation of carbon to roots and root exudates [8][9][10] . ...

... Among various families of known thermoelectric materials (Nolas et al., 2006), the inorganic clathrates have attracted attention of the thermoelectric community in recent years (Cordier and Woll, 1991;Kuhl et al., 1995;Sevov, 1999, 2000;Hermann et al., 1999;Nolas et al., 1999;Chakoumakos et al., 2000;Gryko et al., 2000;Gatti et al., 2003;Kaduk et al., 2003;Paschen et al., 2003;Christensen et al., 2006Christensen et al., , 2010Kishimoto et al., 2007;Deng et al., 2009;Yan et al., 2009). Type I compounds have a general formula of A 8 E 46 and type II compounds have a general formula of A 8 B 16 E 136 . ...

... Adjacent layers though, while separated by electron-donating spacers, can be either coaligned out-of-plane (cf. PbFCl, 111-type 31,32 ; Fig. 3c) or alternating in orientation (ThCr2Si2, 122-type 33,34 ; Fig. 3d) along the c-axis. In view of these topologies, we simulated the powder patterns of 111 and 122 types of FeSe frameworks and compared them with the observed experimental data (Fig. 3b). ...

... Then, based on the results of the TB model, we sweep through the inorganic crystal structure database (ICSD) [50] and discover 298 experimentally synthesized new ideal topological materials, i.e., IAMX family with the stacked distorted kagome and honeycomb lattice (IA = Alkali metal element, M = Rare earth metal element, X = Carbon group element). [51][52][53][54][55] The crystal structure of IAMX family is characterized by the hexagonal lattice with Fe 2 P-type, with the space group of P-62m (No. 189), [56,57] and the interlayer interactions of the IAMX family are chemical bonds rather than the van der Waals forces comparing to the previous studied kagome materials. We perform a high-throughput calculation for IAMX compounds and discover four distinct topological node-ring configurations in the absence of spin-orbital coupling (SOC), which is closely associated with different chemical conditions, including the lattice constants of the structure, interlayer, and intralayer interactions, bond strengths, electronegativity, and so on. ...

... Within this family of compounds, BaGaGe, was first reported to crystallize into the YPtAs-type structure [16], however further studies have shown that it crystallizes in the AlB 2 -type, i.e. the 1H structure with planar honeycomb layers [14,17]. Preliminary data on 1H-BaGaGe suggested a transition to a superconducting state at a critical temperature of T c = 2.4 K [14]. ...

... Amongst the metal substituted ternary clathrates Ba 8 S x Ge 46−x (S = Al, Ni, Cu, Zn, Ga) [13,15,16,[23][24][25][26][27], the Ni substituted Ba 8 Ni x Ge 46−x−y y clathrates are particularly interesting. Since, by varying the concentration of Ni, n-type to p -type doping of the host can be achieved [17,24,28], while maintaining the compositional homogeneity. ...

... a e-mail: n_bouarissa@yahoo.fr (corresponding author) Among the ternary intermetallic compounds, the LiMAl 2 (M = Rh, Pd, Ir and Pt) materials have been studied in great detail in few works [3][4][5][6]. Czybulka et al. [3] have investigated experimentally the structural parameters of the ternary Li 2 MX and LiMX 2 (M = Ru, Rh, Pd, Ir, Pt; X = Al, Ga, In). Except for Li 2 RhIn material, which has a tungsten-type structure, they found that the structures of all other Li 2 MX phases (M = Rh, Ir, Pd, Pt; and X = Al, Ga, In) are derived from the zinc-blende-type (MX) by filling the free tetrahedral and octahedral sites with lithium atoms. ...

... Gallium occupies all three framework sites with a preferential occupancy at the 6c site, as is typical of clathrate-I compositions. [49][50][51][52][53] Figure 1 shows the clathrate-I crystal structure and the crystal used for thermal measurements. Figure 2 shows temperature-dependent isotropic atomic displacement parameters (U iso ). ...