1 / 14

150 likes | 341 Views

Lecture 2: Crystal Structure. PHYS 430/603 material Laszlo Takacs UMBC Department of Physics. Unless we specify otherwise, “solid” means “crystalline,” at least on the microscopic scale.

Download Presentation
## Lecture 2: Crystal Structure

**An Image/Link below is provided (as is) to download presentation**
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.
Content is provided to you AS IS for your information and personal use only.
Download presentation by click this link.
While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

**Lecture 2: Crystal Structure**PHYS 430/603 material Laszlo Takacs UMBC Department of Physics**Unless we specify otherwise, “solid” means**“crystalline,” at least on the microscopic scale • Short range structure reflects the nature of bonds, but the crystal structure also has to conform to translational symmetry: • If we shift the crystal by certain vectors of translation, T, every atom moves into the position of an identical atom. • The possible vectors of translation are linear combinations with integer coefficients of three “primitive translational vectors”: T = na + mb +pc • The entire structure can be described by a “unit cell” defined as a parallelepiped defined by a, b, c and its repeated translations by a, b, c. There can be symmetries beyond translation. • A smallest possible unit cell is the “primitive cell.” • The points in a lattice are mathematical points, we get the crystal structure by putting identical groups of atoms - the basis - on each lattice point. In simple cases, the basis is a single atom.**The elementary vectors of translation, i.e. the unit vectors**of our coordinate system**Find the unit cell**Maurits Cornelis Escher

More Related