Superconductivity in undoped BaFe2As2by tetrahedral geometry design

Superconductivity in CuxBi2Se3 and its implications for pairing in the undoped topological insulator.

Bi2Se3 is one of a handful of known topological insulators. Here we show that copper intercalation in the van der Waals gaps between the Bi2Se3 layers, yielding an electron concentration of approximately 2x10{20} cm{-3}, results in superconductivity at 3.8 K in CuxBi2Se3 for 0.12<or=x<or=0.15. This demonstrates that Cooper pairing is possible in Bi2Se3 at accessible temperatures, with implicati...

Superconductivity in undoped single crystals of BaFe(2)As(2): field and current dependence.

In previous work on undoped MFe(2)As(2), partial drops in the resistivity indicative of traces of superconductivity have been observed for some samples with M =  Ba (T(c)∼20 K, up to 25% drop in ρ) and M =  Ca (T(c)∼10 K, up to 45% drop in ρ). A complete drop in the resistivity to ρ = 0, along with a finite fraction of Meissner flux expulsion, has been observed for M  = Sr, T(c) = 22 K. Using I...

Interface-induced superconductivity at ∼25 K at ambient pressure in undoped CaFe2As2 single crystals.

Superconductivity has been reversibly induced/suppressed in undoped CaFe2As2 (Ca122) single crystals through proper thermal treatments, with Tc at ∼25 K at ambient pressure and up to 30 K at 1.7 GPa. We found that Ca122 can be stabilized in two distinct tetragonal (T) phases at room temperature and ambient pressure: PI with a nonmagnetic collapsed tetragonal (cT) phase at low temperature and PI...

Selection of Suitable Geometry in Compact Heat Exchanger Design

Selection of Suitable Geometry in Compact Heat Exchanger Design