Band structure of energy levels in solids

Improving on the free electron gas treatment of electrons in solids by including a periodic array of atoms leads to a Schrodinger equation that can be solved with Bloch's theorem and boundary condition matching to give band structure in the energy levels. These bands provide a good explanation of the difference between insulators, conductors, and semiconductors, and can help explain how the electrical conductivity of a material changes with temperature. (This lecture is part of a series for a course based on Griffiths' Introduction to Quantum Mechanics. The Full playlist is at www.youtube.com...)

[@thinkofparis]

You absolutely cleared this up for me. I cant say thank you enough. This was a huge help. This topics are not easy to teach to non physics majors.

[@kinchiuho520]

Thanks for this excellent video ,I almost totally understand this topic. but i have a question that what is the physical meaning of n in K=2(pi)n/Na, Does n means the state? Because I know that the horizontal axis (from the graph at 23:00) is related to the energy ,but what is related to the vertical axis. Mathematically , it shows that there are no solution for the cos(Ka) within =+-1 from some Z1 to Z2. Can I take this as there are no energy state in between E1 and E2 ( Where Z1=K1 a & (K1)^2=2mE1/h^2 ) . It will be my pleasure if you answer this question .Again,your videos are awesome and I like the way you explain things. It helps me a lot in physics.Thank you.

[@YossiSirote]

Good video. However, formula at 15:09 (and rest of vid) is confusing as you are using K and k to mean two different periodic things.

[@madisonhoward6004]

Hi Dr. Carlson! Thank you so much for the videos! Can you please do videos on Chapter 6 of Introduction to Quantum Mechanics by Griffiths?

[@mamogamers3147]

This is gold

[@kirtikantsahu3025]

great lecture

[@aubreyhoward2673]

Can you please do chapter 6 (Symmetries and Conservation Laws) from this book? I am really struggling with selection rules for vector operators. Or does anyone know any resources that may cover this chapter for this book? (Griffiths' Introduction to Quantum Mechanics)

[@dylanbeard9770]

Don't insulators have completely full/completely empty energy bands? You made it sound like they are partially filled