Update band_structures.md

6 jobs for intro in 9 minutes and 34 seconds (queued for 1 second)
Status Name Job ID Coverage
  Execute
passed execute_ipynbs #48583

00:06:45

passed mirror to github #48584

00:00:40

 
  Build
passed edx archive #48585

00:00:50

passed ocw website #48587

00:01:07

passed pelican website #48586

00:01:52

 
  Deploy
passed upload test website #48588

00:00:56