A novel method for focus assessment in atomic resolution STEM HAADF experiments

Automatic Alignment of an Orbital Angular Momentum Sorter in a Transmission Electron Microscope Using a Convolutional Neural Network

We report on the automatic alignment of a transmission electron microscope equipped with an orbital angular momentum sorter using a convolutional neural network. The neural network is able to control all relevant parameters of both the electron-optical setup of the microscope and the external voltage source of the sorter without input from the user. It can compensate for mechanical and optical misalignments of the sorter, in order to optimize its spectral resolution. The alignment is completed over a few frames and can be kept stable by making use of the fast fitting time of the neural network.

Towards a holographic approach to spherical aberration correction in scanning transmission electron microscopy

Recent progress in phase modulation using nanofabricated electron holograms has demonstrated how the phase of an electron beam can be controlled. In this paper, we apply this concept to the correction of spherical aberration in a scanning transmission electron microscope and demonstrate an improvement in spatial resolution. Such a holographic approach to spherical aberration correction is advantageous for its simplicity and cost-effectiveness.

Crystal structure assessment of Ge-Sb-Te phase change nanowires

Further improvement of phase change memory devices based on Ge-Sb-Te alloys imposes the reduction of the active cell dimensions to the nanoscale. We investigate the atomic arrangement of Ge(1)Sb(2)Te(4) and Ge(2)Sb(2)Te(5) nanowires. We identify the stacking sequence in each crystal structure by combining the direct observation by High Angle Annular Dark Field imaging and proper simulations. We find out that Ge and Sb atoms randomly share the same lattice sites, although this configuration is considered not stable according to the existing theoretical models elaborated for the bulk material.