Course11310210893 lectures
Crystals, Symmetry and Tensors
Prof. Rajesh Prasad · IIT Delhi
About
Crystallography is fundamental to physics, chemistry, metallurgy, materials science, mechanical engineering, chemical engineering, and any other disciplines dealing with solid state. Despite this importance, due to constraints in design of curriculua a full course is rarely available on this topic. The present course intends to fill this gap. It will begin with basic fundamentals and take the students to advanced concepts of point and space groups symmetry and vector and tensor applications in crystallography.
Intended audience: Students interested in solid state science and engineering will be benefited. UG and PG students of Physics, Chemistry, Metallurgy, Materials Science, Mechanical Engineering, Chemical Engineering will find the course useful.
Lectures
Week 1
- What is Crystal?
- Lattice and Motif
- Lattice Translation
- Unit Cell
- Voronoi Cell
- Unit cell, Basis, Fractional Coordinates
- Miller indices for direction
Week 2
- Miller indices for planes
- Line of intersection between two planes
- Plane normal of a plane for cubic crystal
- Weiss Zone Law
- Application of Weiss Zone Law
- Coordinate transformation
- Reciprocal Basis
- Reciprocal lattice vector (G*_hkl) is perpendicular to plane (hkl)
Week 3
- Length of G*_hkl is reciprocal of interplanar spacing (d_hkl)
- Metric tensor
- Review
- Some properties of metric tensor in real and reciprocal space
- Transformation of direction and planes
- Volume of a crystallographic unit cell
- Orthographic projection of crystals
Week 4
- Stereographic projection-I
- Stereographic projection-II
- Definition of symmetry
- What is a group?
- Matrix Representation of symmetry operation-I
- Matrix Representation of symmetry operation-II
- Trace of a rotation matrix
- Coordinate transformation of a matrix representing symmetry operation
Week 5
- Chirality
- Types of symmetry operation
- Relation between cube and tetrahedron
- 2-fold roto-inversion is a mirror: Proof using matrix method
- Invariance of a trace of symmetry operation during basis transformation
- Crystallographic restriction theorem
- Geometric proof of crystallographic restriction theorem
- Quasicrystals
Week 6
- Affine transformation and Seitz Operator
- Frieze group-I
- Frieze group-II
- 2D point group-I
- 2D point group-II
- The angle between mirrors is half the angle of rotation
- Different kinds of 2D lattices
Week 7
Week 8
- 3D Point Groups I : Introduction
- 3D Point Groups II : Proper Monoaxial Groups
- 3D Point Groups III : Dihedral Groups
- 3D Point Groups IV : Proper cubic point groups
- 3D Point Groups V : Enantiomorphic Point Groups
- 3D Point Groups VI : Improper Monoaxial Point Groups
- 3D Point Groups VII : Combination of a mirror passing through an n-fold axis
- 3D Point Groups VIII : Combination of a mirror perpendicular to an n-fold axis
Week 9
- 3D Point Groups IX : Combination of a mirror perpendicular and parallel to an n-fold axis
- 3D Point Groups X : Mirror parallel to a rotoinversion axis
- 3D Point Groups XI : Improper Cubic Point Groups
- 3D Point Groups XII : Classification of Point Groups into 7 Crystal Systems
- 3D Point Groups XIII : Chirality Revisited
- 3D Point Groups XIV : Centrosymmetric Point Groups
- 3D Point Groups XV : Laue Classes
- 3D Point Groups XVI : Group-Subgroup Relations
- 3D Point Groups XVII : Polar Groups
- 3D Point Groups XVIII : Holohedral or Holosymmetric class
Week 10
- 3D Space Groups I : Introduction
- 3D Space Groups II : Trigonal / Rhombohedral / Hexagonal confusion
- 3D Space Groups III : Bravais Lattices in Trigonal Crystal System
- 3D Space Groups IV : Screw Axes and Screw Operations
- 3D Space Groups V : Glides in 3D
- 3D Space Groups VI : Symmorphic and Nonsymmorphic Space Groups
- 3D Space Groups VII : 73 Symmorphic Space Groups
Week 11
- 3D Space Groups VIII : Interpretation of International Table Page Part -1 : Headline
- 3D Space Groups IX : Interpretation of International Table Page Part -2 : Symmetry Diagrams
- 3D Space Groups X : Interpretation of International Table Page Part -3 : General Position Diagram
- 3D Space Groups XI : Interpretation of International Table Page Part -4 : Origin
- 3D Space Groups XII : Interpretation of International Table Page Part -5 : Asymmetric Unit
- 3D Space Groups XIII : Interpretation of International Table Page Part -6 : Symmetry Operations
- 3D Space Groups XIV : Interpretation of International Table Page Part -7 : Generators Selected
- 3D Space Groups XV : Interpretation of International Table Page Part -8 : Positions
- 3D Space Groups XVI : Interpretation of International Table Page Part -9 : General Position Coordinate Triplet
Week 12
- Representation of Physical Properties of Crystals by Tensors
- Index Notation
- Coordinate Transformation of Vectors
- Some properties of Coordinate Transformation matrix between two orthonormal bases
- Coordinate Transformation for a second rank tensor
- Coordinate Transformation of tensors of different rank
- Magnitude of a second rank tensor property in a given direction
- Neumann's Principle
- Physical properties represented by second rank tensors are CENTROSYMMETRIC
- Effect of symmetry on the components of tensor representing a physical property
- Cubic crystals are isotropic for second rank tensor properties
Syllabus and materials
At NPTEL, as the course publishes them.
Credits and licence
- Institution
- IIT Delhi
- Department
- Metallurgy and Material Science
- Teacher
- Prof. Rajesh Prasad
- Level
- Undergraduate
- Language
- English
- Subjects
- Engineering
- Source
- NPTEL
- Licence
- CC BY-NC-SA, as NPTEL states it. Non-commercial use only. NPTEL's terms
- Attribution
- NPTEL states: "Distributed under Creative Commons Attribution-ShareAlike / CC BY - NC - SA", beside a BY-NC-SA badge.
- Who can watch
- NPTEL gives no rating. Invisible Network shows it to Tweens profiles and older, judged from what the source says about it. How courses are placed