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We report on the current status of the Adaptive X-ray Optics project run by Lawrence Livermore National Laboratory (LLNL). LLNL is collaborating with the Advanced Light Source (ALS) to demonstrate a near real-time adaptive X-ray optic. To this end, a custom-built 45 cm long deformable mirror has been installed at ALS beamline 5.3.1 (end station 2) for a two-year period that started in September 2014. We will outline general aspects of the instrument, present results from a recent experimental campaign and touch on future plans for the project.

We have studied in situ fractured surfaces of single-crystal ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_{3}$ with hard x-ray photoemission (HXPS) at an excitation energy of 7.7 keV. These more bulk-sensitive measurements reveal low-binding-energy satellites in the $\text{Mn}\text{ }2{p}_{3/2}$, $3s$, and $3p$ core spectra that are in agreement with previously observed satellites in $\text{Mn}\text{ }2{p}_{3/2}$ for other strongly correlated materials, and which have been interpreted in terms of nonlocalized screening effects. The $\text{Mn}\text{ }3s$ spectrum is consistent with recent soft x-ray measurements [N. Mannella et al., Phys. Rev. Lett. 92, 166401 (2004)] in showing an increased multiplet splitting at temperatures 100 K or more above the Curie temperature, although the magnitude of the effect is somewhat reduced. The valence-band spectra exhibit significant enhancement of intensity at such higher temperatures that we interpret as evidence of localization of $\text{Mn}\text{ }3d$-derived charge, which is in agreement with the multiplet splitting change and prior soft x-ray work. Additional aspects of HXPS for the study of complex materials are thus demonstrated.

We study spin-half and spin-one Heisenberg models in the limit where one dimensional (1-D) linear chains, with exchange constant J1, are weakly coupled in an anisotropic triangular lattice geometry. Results are obtained by means of linked-cluster series expansions at zero temperature around different magnetically ordered phases. We study the non-colinear spiral phases that arise classically in the model and the colinear antiferromagnet that has been recently proposed for the spin-half model by Starykh and Balents using a Renormalization Group approach. We find that such phases can be stabilized in the spin-half model for arbitrarily small coupling between the chains. For vanishing coupling between the chains the energy of each phase must approach that of decoupled linear chains. With increasing inter-chain coupling, the non-colinear phase appears to have a lower energy in our calculations. For the spin-one chain, we find that there is a critical interchain coupling needed to overcome the Haldane gap. When spin-one chains are coupled in an unfrustrated manner, the critical coupling is very small (~0.01J1) and agrees well with previous chain mean-field studies. When they are coupled in the frustrated triangular-lattice geometry, the critical coupling required to develop magnetic order is substantially larger (> 0.3J1). The colinear phase is not obtained for the spin-one Heisenberg model., 7 pages, 8 figures