A challenge of hybrid perovskite solar cells is device instability, which calls for an understanding of the perovskite structural stability and phase transitions. Using neutron diffraction and first-principles calculations on formamidinium lead iodide (FAPbI3), we show that the entropy contribution to the Gibbs free energy caused by isotropic rotations of the FA+ cation plays a crucial role in ...

We report neutron diffuse scattering measurements on highly magnetostrictive Fe1-xGax alloys (0.14<x<0.20) with different thermal treatments. This diffuse scattering scales with magnetostriction and exhibits asymmetric peaks at the (100) and (300) reciprocal lattice positions that are consistent with the coexistence of short-range ordered, coherent nanometer-scale precipitates embedded in a lon...

A remarkable result of [Segre43] says that a smooth cubic surface over Q is unirational iff it has a rational point. [Manin72, II.2] observed that similar arguments work for higher dimensional cubic hypersurfaces satisfying a certain genericity assumption over any infinite field. [CT-S-SD87, 2.3.1] extended the result of Segre to any normal cubic hypersurface (other than cones) over a field of ...

We report an experimental study on optical and magneto-optical properties of Cesubstituted yttrium iron garnet thin films incorporating gold nanoparticles. Au nanoparticles were formed by heating Au thin film on cubic quartz and garnet substrate in vacuum chamber and a Ce:YIG layer was deposited on them by the aid of Pulsed laser deposition method. A large enhancement of the longitudinal Kerr e...

Using symmetry considerations, we identify three families of large photonic band-gap (PBG) architectures defined by the isointensity surfaces of four beam laser interference. For particular choices of beam intensities, directions, and polarizations, we obtain a diamondlike crystal, a novel body-centered cubic architecture, and a simple cubic structure with PBG to center frequency ratios of 25%,...

We calculate rigorous lower bounds for the ground-state degeneracy per site, W, of the q-state Potts antiferromagnet on slabs of the simple cubic lattice that are infinite in two directions and finite in the third and that thus interpolate between the square (sq) and simple cubic (sc) lattices. We give a comparison with large-q series expansions for the sq and sc lattices and also present numer...

To a family of smooth projective cubic surfaces one can canonically associate a family of abelian fivefolds. In characteristic zero, we calculate the Hodge groups of the abelian varieties which arise in this way. In arbitrary characteristic we calculate the monodromy group of the universal family of abelian varieties, and thus show that the Galois group of the 27 lines on a general cubic surfac...

We construct the cubic interaction vertex and dynamically generated supercharges in lightcone superstring field theory for a large class half-supersymmetric D-branes in the planewave background. We show that these satisfy the plane-wave superalgebra at first order in string coupling. The cubic interaction vertex and dynamical supercharges presented here are given explicitly in terms of oscilato...

We present a heuristic for finding a large induced matching of cubic graphs. We analyse the performance of this heuristic, which is a random greedy algorithm, on random cubic graphs using differential equations and obtain a lower bound on the expected size of the induced matching, M, returned by the algorithm. A corresponding upper bound is derived by means of a direct expectation argument. We ...

We present a simple, yet efficient, heuristic for finding a large 2-independent set of cubic graphs. We analyse the performance of this heuristic, which is a randomised greedy algorithm, on random n-vertex cubic graphs using differential equations. In this way, we are able to prove that the expected size of the 2-independent set returned by the algorithm is asymptotically almost surely greater ...