Conductor band overlap definition question

In summary, the conversation discusses the concept of overlapping valence and conduction bands in metals and whether there are any examples of metals with separated bands. The topic also touches on the properties of semiconductors and the definition of a metal. The speaker suggests researching the electronic structure of different materials to gain a better understanding. The discussion also mentions the use of doped graphene and the material PbS as examples of conductors with small bandgaps. The conversation concludes by acknowledging the subjective nature of determining whether a material is a conductor, insulator, or semiconductor.
  • #1
td21
Gold Member
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i search all over the web but i cannot find the definition. Although I find all the literature saying that metal have valence band and conduction band overlapped, (and I cannot find a metal example with valence band and conduction band not being overlapped), I wonder if there is a conductor(including metal) example with valence band and conduction band being separated with an infinitesimal width such that valence electron can jump easily thermally.
I know this is semiconductor properties but with gap being very small then does this make the situation being conducting at temperature bigger than but not equal to 0K?
I appreciate the helps provided by physicsforums and thank you so much.
 
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  • #2
I've seen the phrase "overlapping conduction and valence band", but I think it's a historical appendage that's not useful anymore. See if you can find the full k-dependent electronic structure of various semiconductors and metals and compare them. The solution to your question should become apparent.

The only very small gap I know of is doped graphene.
 
  • #3
The definition of a metal as a solid with "overlapping conduction and valence band" is still useful (and used).

There is a gradual progression from conduction to insulation and small bandgap materials will seem like conductors (perhaps poor conductors) and common temperatures. One example is PbS, or Galena, which was the first semiconductor used commercially (before it was known it was a semiconductor, or even what a semiconductor was!). It can be used as a conductor in many situations.

Whether a material is a conductor or insulator or semiconductor can depend on your point of view. Most people think of diamond as an insulator but it can be used as a semiconductor if it is biased appropriately.
 

1. What is the definition of conductor band overlap?

Conductor band overlap refers to the overlapping of energy bands in a material, specifically in a conductor. This overlap allows for the free movement of electrons, making the material a good conductor of electricity.

2. How does conductor band overlap affect the conductivity of a material?

The amount of overlap in the conductor band directly affects the conductivity of a material. The greater the overlap, the better the material will conduct electricity.

3. Can conductor band overlap be modified in a material?

Yes, conductor band overlap can be modified by changing the structure or composition of a material. For example, doping a semiconductor with impurities can create a larger overlap and increase its conductivity.

4. How is conductor band overlap related to the band gap of a material?

Conductor band overlap and band gap are inversely related. A larger overlap results in a smaller band gap, and vice versa. This is because a larger overlap allows electrons to move more freely between energy bands, making it easier for them to conduct electricity.

5. What are some real-world applications of conductor band overlap?

Conductor band overlap has many applications in the field of electronics and technology. It is essential for the functioning of conductors and semiconductors, which are used in various devices such as computers, smartphones, and solar cells. It also plays a crucial role in the design of electronic circuits and in the development of new materials for advanced technologies.

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