Question

In: Physics

In the band diagram of potassium, the valence band would be: a) completely filled b) partially...

In the band diagram of potassium, the valence band would be:

a) completely filled
b) partially filled
c) completely empty
d) nonexistent

I know the answer is a), but could someone clearly explain to me why this is?

Solutions

Expert Solution

According to the definition of the valence band and conduction band, the valence band is defined as the band is the highest band which is completely filled at absolute zero and the next band which is either partially filled or completely empty is called conduction band.

So at absolute zero temperature, the valence band is always completely filled independent of the material and indeed by the definition of valence band the option ''a.'' is correct.

Further at zero temperature as I said the valence band is completely filled and conduction band may be partially filled or completely empty as they are separated by a band gap. But at a non-zero temperature, you cannot say that valence band of a material is completely filled because at a non zero temperature the conduction band (band next to the valence band ) have always a non-zero probability(due to Fermi function) that its states are filled with electron so it is always partially filled at non-zero temperature.

In conclusion, it can be said that the valence band is always completely filled at absolute zero but at non zero temperature it is always partially filled.


Related Solutions

Draw band structure diagrams for the following, highlighting on each diagram the valence band, conduction band...
Draw band structure diagrams for the following, highlighting on each diagram the valence band, conduction band and the band gap. (a) Au, (b) SiO2 (c) intrinsic Ge (d) p-type Ge (e) n-type Ge On each of the band diagrams also indicate the probable location of the Fermi level for (c), (d) and (e) at a temperature of 0 K.
-Find the energy-momentum relation for electrons in conduction band and for holes in valence band of...
-Find the energy-momentum relation for electrons in conduction band and for holes in valence band of a quantum well.
What does it mean when two loci are(a) unlinked(b) partially linked(c) completely linked?...
What does it mean when two loci are(a) unlinked(b) partially linked(c) completely linked?Explain with respect to the expected phenotypic ratios in the F2 in a typical Mendelian dihybrid testcross (e.g. Assume two loci, A and B, with two alleles each, such that the A and B alleles are completely dominant over a and b).
a) The probability that a state is filled at the conduction band edge (Ec) is precisely...
a) The probability that a state is filled at the conduction band edge (Ec) is precisely equal to the probability that a state is empty at the valence band edge (Ev). Where is the Fermi level is located? b) Where is located the Fermi energy in an insulator and metal as compared to a semiconductor? Show on a schematic band diagram the amounts of carrier populations or concentrations in an intrinsic, n-type and p-type semiconductor?
For which of the following elements the valence band will be full? Explain how you arrive...
For which of the following elements the valence band will be full? Explain how you arrive at your answer: sodium, magnesium, aluminum and silicon Based on the answer, predict which of these elements will be metal, and which may not be metal. Then compare your prediction with the actual observations.
Give the energy band description of conductor, semiconductor and insulator. Why are the valence electrons so...
Give the energy band description of conductor, semiconductor and insulator. Why are the valence electrons so important in the materials?
Diagram a mechanism of action for the sodium potassium ATPase.
Diagram a mechanism of action for the sodium potassium ATPase.
A balloon is filled up completely with helium gas and left in a room with a...
A balloon is filled up completely with helium gas and left in a room with a controlled temperature of 230C. After two days of being in the same room, the balloon was found to have shrunk to half its filled-up size. However, there was no leakage of helium gas from the balloon during the two days. Explain what happened to the pressure inside the balloon due to the change in the size of the balloon. ?  Use Boyle's Law to explain...
1. Draw and label the band diagram for Carbon Monosulfide anion(CS^-) 2. Draw the MO diagram...
1. Draw and label the band diagram for Carbon Monosulfide anion(CS^-) 2. Draw the MO diagram for Carbon Monosulfide anion (Cs^-) and give bond order.
Describe below (briefly) a) the motivation for hybridization in valence bond theory and b) why valence...
Describe below (briefly) a) the motivation for hybridization in valence bond theory and b) why valence bond theory cannot predict magnetism. In your answer, make sure to include a description of how molecular orbital theory addresses magnetism.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT