click below

click below

Normal Size Small Size show me how

# solid state physics

Term | Definition |
---|---|

What is solid-state physics? | the study of solids through methods such as crystallography and electromagnetism. the largest branch of condensed matter physics. It studies how the large-scale properties of solid materials result from their atomic-scale properties. |

what have you learnt in solid-state physics? | two kinds of solids. Crystalline solids and amorphous solids. the properties of them. basic concepts such as unit cell and structure of crystalline. also miller indices and atomic packing factor. the application of Bragg's law . |

Explain the two kinds of solids. | for crystalline, the atoms, molecules or ions pack together in an ordered arrangement. Such solids typically have flat surfaces, with unique angles between faces and unique 3 dimensional shape. eg, diamond, quartz crystal. more focused on crystalline. |

Explain the two kinds of solids. | In amorphous solids, the structure is not ordered. There's no well-defined faces, angles or shapes. These solids are often mixtures of molecules which do not stack together well or large flexible molecules. eg. glass, water, rubber. |

what is a unit cell? | unit cell is a tiny box containing one or more atoms. they are stacked in 3-dimensional space that describes the arrangement of atoms of the crystal. the unit cell plus translational operators along x y z axis then we get the crystalline solid. |

how is the structure of crystalline | crystalline is constructed by repeating structural unit, which is what we called unit cells. |

common crystal structures | simple-cubic, body-centred cubic, face-centred cubic. |

what is crystal lattice? | By replacing each group of atoms by a representative point a crystal lattice is obtained. |

use lattice to represent structure of crystalline solids | associate every lattice point with one or more atoms- called the basis or pattern. When basis is repeated with lattice in all directions, it gives the actual crystal structure. basis+lattice=crystal structure. crystal structure real lattice imaginary. |

example of crystal structure | Nacl. |

what is miller indices | miller indices denotes a plane that intercepts the three points, x/l,y/m,z/n, or some multiple thereof. the miller indices are proportional to the inverse of the intercepts of the plane with the unit cell. |

how to get miller indices? | 1in the basis of lattice vectors, confirm the intercepts of three vectors;2take the reciprocals3simplify them to the simplest ratio of integers. represent in the form of (l,m,n), that is miller index. |

atomic packing factor(APF) | APF=Volume of atoms in unit cell/ Volume of unit cell |

bragg's law | when a crystal is bombarded with x-rays of a fixed wavelength, at a certain incident angle, the waves of the scattered x-rays interfere constructively and then produce intense reflected rays |