Crystal cleavage means that the crystal fracture surface is separated along a certain crystal surface (cleavage surface) under the action of normal stress. For two-dimensional layered materials, the inner layer is bound by strong covalent bond or ionic bond, while the interlayer is mostly dependent on weak van der Waals force. Generally, the simple ceramic stick and glue method can peel out fresh and high-quality crystal surface. However, for materials with three-dimensional properties, such as metal or semiconductor materials, it is difficult to obtain smooth cleavage planes due to strong interlayer forces.

The cryogenic in-situ cleavage system developed by Fermion Instruments can realize the cleavage of semiconductor single crystal and hard ion crystal under high vacuum and low temperature conditions. Ultra-high vacuum can protect the fresh sample surface, while low temperature can improve the brittleness of the sample and obtain a smoother cleavage surface. The equipment is vacuum-connected with the surface analysis equipment to realize in-situ dissociation, polishing and transfer of the whole process, meet different users’ experimental research on the surface properties of various materials, and expand a more abundant sample source for angular resolution photoelectron spectroscopy (ARPES) and scanning tunneling microscope (STM).