Fyzikální ústav Akademie věd ČR

Abstract: We study the evolution of structural and electronic properties of layered semiconducting transition metal dichalcogenides, MoX2 (X = S, Se, Te) upon increasing pressure, employing ab initio DFT calculations in combination with metadynamics and evolutionary search. We found that in MoS2 a layer sliding structural transition occurs at 20 GPa, converting the 2Hc stacking stable at ambient pressure to the 2Ha stacking (known in 2H-NbSe2)[1].

Tightly focused electromagnetic radiation (an optical beam) can be used to capture a small particle without physically touching it. This technique, which has led to a Nobel prize in physics and a whole new industry in biotechnology, could allow for example to explore new physical regimes when it is combined with cooling the particle to its quantum ground state.

The Spallation Neutron Source became in 2007 the brightest pulsed Neutron Source and by now is ~8 times brighter than the second leading pulsed Neutron Source. It took years of learning and understanding issues and find better solutions or work arounds. After an introduction into the workings of the Spallation Neutron Source and its Frontend, we will discuss some of the discoveries made and exploited for the success of SNS, including the record breaking H- beam currents and the record breaking service cycles of the SNS H- ion source.