Large size (∼2 cm) single crystals of layered MoTe2 in both 2H- and 1T′-types were synthsized using TeBr4 as the source of Br2 transport agent in chemical vapor transport growth. The crystal structures of the as-grown single crystals were fully characterized by X-ray diffraction, Raman spectroscopy, scanning transmission electron microscopy, scanning tunneling microscopy (STM), and electrical resistivity (ρ) measurements. The resistivity ρ­(T), magnetic susceptibility χ­(T), and heat capacity C p(T) measurement results reveal a first order structural phase transition near ∼240 K for 1T′-MoTe2, which has been identified to be the orthorhombic Td-phase of MoTe2 as a candidate of Weyl semimetal. The STM study revealed different local defect geometries found on the surface of 2H- and Td-types of MoTe6 units in trigonal prismatic and distorted octahedral coordination, respectively.

We report crystal growth, AC and DC magnetic susceptibilities [χ(T, H)], magnetization [M(T, H)], and heat capacity [C P (T, H)] measurement results of GdSbTe single crystal. GdSbTe is isostructural to the confirmed nonmagnetic nodal-line semimetal ZrSiS of noncentrosymmetric tetragonal crystal structure in space group P4/nmm (No. 129), but it shows additional long-range antiferromagnetic spin ordering for the Gd spins of S = 7 / 2 below T N . Both χ(T, H) and C P (T, H) measurements confirm the existence of a long-range antiferromagnetic (AFM) spin ordering of Gd spins below T N ∼ 12 K, and an additional spin reorientation/recovery (sr) behavior is identified from the change of on-site spin anisotropy between T sr1 ∼ 7 and T sr2 ∼ 4 K. The anisotropic magnetic susceptibilities of χ(T, H) below T N clearly demonstrate that the AFM long-range spin ordering of GdSbTe has an easy axis parallel to the ab-plane direction. The fieldand orientation-dependent magnetization of M(T, H) at 2 K shows two plateaus to indicate the spin-flop transition for H||ab near ∼2.1 T and a metamagnetic state near ∼5.9 T having ∼ 1 / 3 of the fully polarized magnetization by the applied field. The heat capacity measurement results yield Sommerfeld coefficient of γ ∼ 7.6(4) mJ/mol K 2 and θ D ∼ 195(2) K being less than half of that for the nonmagnetic ZrSiS. A three-dimensional (3D) AFM spin structure is supported by the ab initio calculations for Gd having magnetic moment of 7.1 μ B and the calculated AFM band structure indicates that GdSbTe is a semimetal with bare density of states (0.36 states/eV fu) at the Fermi level, which is 10 times smaller than the measured one to suggest strong spin-fluctuation.

Zeolites are aluminosilicates with extensive application both commercially and in materials science. Current applications include dehydrating natural gas and in humidity sensors. Synthesis of new frameworks is an important area of research in chemistry and materials science. The Zeolite LTA framework in particular is getting much attention in this area due to its potential for application. Topological indices are graph invariants which provide information on the structure of graphs and have proven very useful in quantitative structure activity relationships (QSAR) and quantitative structure property relationships (QSPR) at predicting important chemico-phyiscal aspects of chemical compounds. In this paper we compute nine of the most significant distance based topological indices of the Zeolite LTA framework and thirteen valency based molecular descriptors. OPEN ACCESS RECEIVED

The anisotropic superconducting properties of PbTaSe single crystal is reported. Superconductivity with T =  3.83  ±  0.02 K has been characterized fully with electrical resistivity ρ(T), magnetic susceptibility χ(T), and specific heat C (T) measurements using single crystal samples. The superconductivity is type-II with lower critical field H and upper critical field H of 65 and 450 Oe (H⊥  to the ab-plane), 140 and 1500 Oe (H|| to the ab-plane), respectively. These results indicate that the superconductivity of PbTaSe is anisotropic. The superconducting anisotropy, electron-phonon coupling λ , superconducting energy gap Δ, and the specific heat jump ΔC/γT at T confirms that PbTaSe can be categorized as a bulk superconductor.

The crystal structure and magnetic, electronic, and thermal properties of a NdSbTe single crystal were examined by X-ray diffraction, magnetic and specific heat C p (T) measurements, and density functional theory (DFT) calculations. NdSbTe undergoes an antiferromagnetic ordering at T N ≈ 2.9 K, which is obviously shown from χ(T) and C p (T). With increasing H, a spinflop transition is induced along the c axis, and subsequently AFM disappeared at H ≤ 0.4 T and H ≤ 2.5 T along H||c and H||ab, respectively. This remarkable observation shows that the ordered Nd 3+ moments lie in the c axis and that there is the existence of an anisotropy scenario. The estimated magnetic anisotropy with χ ||c (0.63)/χ ||ab (0.036) is 17.5 at temperature 1.8 K. An analysis of specific heat capacity reveals the significant contribution of crystal field effects at high temperature. We carried out DFT calculations to predict the magnetic ground state and the electronic properties of NdSbTe. Our calculations revealed that the magnetic ground state is AFM with spins aligned ferromagnetically along the b axis and antiferromagnetically along the c axis. The calculated electronic band of NdSbTe exhibits a Dirac semimetal material nature.