## Condensed Matter

## aka Solid State Physics, or Statistical Mechanics

- Superconductivity of Metals
- Blackbody radiation
- Planck's Quantum Hypothesis
- Wien's law from Planck's radiation formula
- Stefan-Boltzmann law
- Plancks radiation formula for Intensity
- de Broglie wavelength
- Interaction energy between 2 atoms
- Force required to break a molecule
- Chemical Bonding
- Van Der Waals Equation
- Isothermal Compressibility
- Weiss mean-field decoupling
- Sublattice magnetization
- Hamiltonian
- Neel (ordering) temperature
- Uniform spin susceptibility
- Staggered external field with staggered susceptibility
- Calculation of mole, atoms, volume, atomic radius, atomic mass
- Miller indices
- Primitive cell within face-centered cubic cell
- Diatomic harmonic chain
- Dispersion relation for chain of atoms with acoustic and optical branch
- Frequency and wavelength
- Brillouin zone
- Debye temperature
- Specific heat
- Wien's Law
- Mean free time between electron collisions
- Resistivity
- Current
- Hall coefficient
- Electric field
- Hall effect
- Finding the conductivity, carrier density, mobility, fermi velocity
- Fermi energy
- Band Theory
- Fermi level
- Conduction band
- Valence band
- Energy gap (band gap)
- Solids: Insulators, Semiconductors, Conductors
- Electrical conduction at different temperatures
- Charge carriers
- Dimerized, conjugated polymers
- Polyacetylene Chain and Simple Chain
- Band folding
- Density of states
- Feyman model of energy bands
- Energy dispersion of electrons in a cubic lattice
- Effective mass and band width
- Electronic Density of State
- Free electron energy dependence
- History of the electrical conductivity of metals

### Problem 1

According to the BCS theory, the attraction between Cooper pairs in a superconductor is due to

- vacuum polarization
- interactions with the ionic lattice
- the Casimir effect
- the strong nuclear force
- the weak nuclear force

### Solution 1

B### Problem 2

Which of the following ions CANNOT be used as dopant in germanium to make an n-type semiconductor?

- N
- Sb
- As
- B
- P

### Solution 2

D

### Problem 3

The conventional unit cell of a body-centered cubic Bravias lattice is shown in the figure above. The conventional cell has volume a^{3}. What is the volume of the primitive unit cell?

- a
^{3}/ 8 - a
^{3} - a
^{3}/ 4 - 2 a
^{3} - a
^{3}/ 2

### Solution 3

E

### Problem 4

Which of the following best represents the temperature of the resistivity of an undoped semiconductor?

### Solution 4

C

### Problem 5

Which of the following statements concerning the electrical conductivities at room temperature of a pure copper sample and pure silicon sample is FALSE?

- The conductivity of the copper sample is many orders of magnitude greater than that of the silicon sample.
- The addition of impurity in the silicon sample always decreases its conductivity
- The addition of impurity in the copper sample always decreases its conductivity
- If the temperature of the silicon sample is increased, its conductivity will decrease.
- If the temperature of the copper sample is increased, its conductivity will decrease.

### Solution 5

A