QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Adila on March 25, 2016, 06:44

Title: Width variation of phosphorene and energy gap
Post by: Adila on March 25, 2016, 06:44

Dear all,

I had varied the width of phosphorene by changing the repetition number in b or c direction. However, the energy band gap does not change. Supposedly, according to other published papers, the energy band gap decreases as the width increases. Anyone know what is wrong?

Thank you in advanced for your response.

Title: Re: Width variation of phosphorene and energy gap
Post by: zh on March 25, 2016, 12:12

What you have calculated may be just the different size of repeated unit cells of phosphorene. So you obtained the same band gaps in all these calculations.

You should increase the atomic layers of phosphorene.    Suppose the phosphorene layer is placed in the xy plane,  you should increase the number atomic layers along the z direction (Note: this doesn't mean that you increase the repetition number of unit cell along z direction), that is, put more atomic layers of phosphorene in the unit cell whose a and b are unchanged. If the vacuum thickness is kept same, the lattice constant c will increase because the number of atomic layers is increased.

Title: Re: Width variation of phosphorene and energy gap
Post by: Adila on March 27, 2016, 02:38

Dear zh,
 
First of all, thank you for your reply. If I am supposed to increase the number of atomic layer of phosphorene, does it mean that I am increasing its thickness? If that is so, it means that I am changing the thickness, not the width. Am I wrong?

However, I will try according to your suggestion.

Thank you.  :)

Title: Re: Width variation of phosphorene and energy gap
Post by: zh on March 28, 2016, 01:45

"increase the number of atomic layer of phosphorene"  = "increase the thickness of phosphorene".