https://www.researchgate.net/post/Is_it_possible_to_culculate_the_effective_mass_in_the_metal_nano_particle

https://www.researchgate.net/post/Can_the_effective_mass_of_an_electron_or_a_hole_be_greater_or_less_than_its_actual_mass2/1

Thanks Miss Diman for this information's

you are welcome

Miss Diman but Still I want formula for effective mass

Do you mean in nanosize ?

I hope this paper is useful. 

thanks Miss Diman, its so helpfull, if you have more files pls could you send to me, thanks again

 hi Dr .I sent you some article I hope that it help you.

all the best 

Thanks a lot Excellent papers