A symmetry-oriented crystal structure prediction method for crystals with rigid bodies.

We have developed an efficient crystal structure prediction (CSP) method for desired chemical compositions, specifically suited for compounds featuring recurring molecules or rigid bodies. We applied this method to two metal chalcogenides: LiPSand NaGeSe, treating PSas a tetrahedral rigid body and GeSeas an ethane-like dimer rigid body. Initial trials not only identified the experimentally observed structures of these compounds but also uncovered several novel phases, including a new stannite-type LiPSstructure and a potential stable structure for NaGeSethat exhibits significantly lower energy than the observed phase, as evaluated by density functional theory calculations.

Lithium selenometallates of triel elements, LiMSe (M = Al and Ga), aliovalent doping and their ionic conductivity.

Ternary selenometallates, LiMSe (M = Al(I) and Ga(II)), have been synthesized for the first time through high temperature solid-state reactions combining elements and LiSe in stoichiometric compositions. LiMSe crystallizes in the 2/ space group, forming a pseudo-2D layer type structure with edge sharing LiSe and MSe tetrahedra along the -axis. These layers are interleaved by octahedrally coordinated Li ions located in the interlayer space.

Discovery of an olivine-type lithium manganese thiophosphate, LiMnPS, a building block approach.

An olivine-type orthothiophospate LiMnPS has been synthesized for the first time through a building block approach by reacting preformed ternary lithium thiophospate with MnCl. Diffuse reflectance measurements show an optical band gap of 2.36 eV, which is further confirmed by DFT calculations.

The effect of interface angle on the thermal conductivity of Si/Ge superlattices.

Si/Ge superlattices (SLs) are good candidates for thermoelectric materials because of their remarkable thermal insulating performance compared with their bulk counterparts. In this paper, the non-equilibrium molecular dynamics (NEMD) simulation method was applied to investigate the thermal conductivity of Si/Ge SLs containing tilted interfaces. It was found that the thermal conductivity will be 4-5 times higher than that of other angles when the period length is 4-8 atomic layers and the interface angle is 45°.