T. Palasyuk

Electronic and magnetic phase diagram of β -Fe 1.01 Se with superconductivity at 36.7 K under pressure

In this letter, we report that the superconductivity transition temperature in beta-Fe1.01Se increases from 8.5 to 36.7 K under applied pressure of 8.9 GPa. It then decreases at higher pressure. A dramatic change in volume is observed at the same time Tc rises, due to a collapse of the separation between the Fe2Se2 layers. A clear transition to a linear resistivity normal state is seen on cooling at all pressures. No static magnetic ordering is observed for the whole p-T phase diagram. We also report that at higher pressure (starting around 7 GPa and completed at 38 GPa), Fe1.01Se transforms to a hexagonal NiAs-type structure and displays non-magnetic, insulating behavior. The inclusion of electron correlation in band structure caculations is necessary to describe this behavior, signifying that such correlations are important in this chemical system. Our results strongly support unconventional superconductivity in beta-Fe1.01Se.

Electronic and magnetic phase diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure

In this letter, we report that the superconductivity transition temperature in beta-Fe1.01Se increases from 8.5 to 36.7 K under applied pressure of 8.9 GPa. It then decreases at higher pressure. A dramatic change in volume is observed at the same time Tc rises, due to a collapse of the separation between the Fe2Se2 layers. A clear transition to a linear resistivity normal state is seen on cooling at all pressures. No static magnetic ordering is observed for the whole p-T phase diagram. We also report that at higher pressure (starting around 7 GPa and completed at 38 GPa), Fe1.01Se transforms to a hexagonal NiAs-type structure and displays non-magnetic, insulating behavior. The inclusion of electron correlation in band structure caculations is necessary to describe this behavior, signifying that such correlations are important in this chemical system. Our results strongly support unconventional superconductivity in beta-Fe1.01Se.

Exotic magnetism in the alkali sesquioxides Rb4O6 and Cs4O6

Among the various alkali oxides the sesquioxides

Ammonia as a case study for the spontaneous ionization of a simple hydrogen-bonded compound

{\text{Rb}}_{4}{\text{O}}_{6}

Superconductivity at 36 K in beta-Fe1.01Se with the compression of the interlayer separation under pressure

and

High-pressure study of tetramethylsilane by Raman spectroscopy

{\text{Cs}}_{4}{\text{O}}_{6}

Chemically driven negative linear compressibility in sodium amidoborane, Na(NH2BH3).

are of special interest. Electronic-structure calculations using the local spin-density approximation predicted that

Structure and electrical resistivity of mixed-valent EuNi2P2 at high pressure

{\text{Rb}}_{4}{\text{O}}_{6}

Hydrogen-mediated affinity of ions found in compressed potassium amidoborane, K[NH2BH3]

should be a half-metallic ferromagnet, which was later contradicted when an experimental investigation of the temperature-dependent magnetization of

Pressure effect on superconductivity in FeSe0.5Te0.5

{\text{Rb}}_{4}{\text{O}}_{6}