low thermal creep, such as turbine blades. Here, the absence of grain boundaries actually gives a decrease in yield strength, but more importantly decreases the amount of creep which is critical for high temperature, close tolerance part applications. Researcher Barry Piearcey found that a right-angle bend at the casting mold would decrease the number of columnar crystals and later, scientist Giamei used this to start the single-crystal structure of the turbine blade. In research Single crystals are essential in research especially condensed-matter physics and all aspects of materials science such as surface science. The detailed study of the crystal structure of a material by techniques such as Bragg diffraction and helium atom scattering is easier with single crystals because it is possible to study directional dependence of various properties and compare with theoretical predictions. Furthermore, macroscopically averaging techniques such as angle-resolved photoemission spectroscopy or low-energy electron diffraction are only possible or meaningful on surfaces of single crystals. In superconductivity there have been cases of materials where superconductivity is only seen in single-crystalline specimen. They may be grown for this purpose, even when the material is otherwise only needed in polycrystalline form. As such, numerous new materials are being studied in their single-crystal form. The young field of metal-organic-frameworks (MOF's) is one of many which qualify to have single crystals. In January 2021 Dr. Dong and Dr. Feng demonstrated how polycyclic aromatic ligands can be optimized to produce large 2D MOF single crystals of sizes up to 200 μm. This could mean scientists can fabricate single-crystal devices and determine intrinsic electrical conductivity and charge transport mechanism. The field of photodriven transformation can also be involved with single crystals with something called single-crystal-to-single-crystal (SCSC) transformations. These provide direct observation of molecular movement and understanding of mechanistic details. This photoswitching behavior has also been observed in cutting-edge research on intrinsically non-photo-responsive mononuclear lanthanide single-molecule-magnets (SMM). See also Engineering aspects of crystallisation Fractional crystallization Laser-heated pedestal growth Micro-pulling-down Recrystallization Seed crystal References Further reading "Small Molecule Crystallization" (PDF) at Illinois Institute of Technology website Crystals