Thin-film crystalline structure with surfaces having selected plane orientations

A method of forming a thin film structure, comprising:

• performing one or more repetitions to form a template on a substrate, the template used to form a structure having a first surface parallel to the substrate and a second surface orthogonal to the first surface, the repetitions comprising:
• depositing a layer of a template material to a first thickness T1;
• and
• ion beam milling the layer of the template material to remove thickness T2, where T2<T1, resulting in a layer of the template material with thickness T1−T2, wherein the ion beam milling is at an angle that results in a first majority of crystalline grains at the first surface being oriented at a first plane orientation to have a first atomic packing factor at the first surface and a second majority of crystalline grains at the second surface oriented at a second plane orientation to have a second atomic packing factor;
• and
• depositing additional material on the template to form the structure, the additional material having a same crystalline microstructure as the template material.