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Units for effective mass

  • Thread starter magnifik
  • Start date
  • #1
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Are the units for effective mass in kg? I have been trying to wrap my head around the concept then realized I wasn't even sure about the units.

The formula is: m* = (h/2pi)2(d2E/dk2)-1

the units of h are in J-s, and the units of E are in J so...
(J-s)2/J = J-s2
J = kg m2/s2
kg m2 s2/s2 = kg m2

why am i left with a m2 unit??
 

Answers and Replies

  • #2
phyzguy
Science Advisor
4,506
1,447
k has units of inverse length. You have a k^2 in the numerator, which has units of m^-2, which will cancel the m^2, and leave you with m* having units of kg, which is correct.
 

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