QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: GJK on May 14, 2019, 09:23

Title: Band structure Energy
Post by: GJK on May 14, 2019, 09:23

Hi,

1. We are getting bandstruture diagram appearing as Energy Vs Brillouin zone. What does that diagram signify in our software--Is it E-E_F Vs Brillouin zone (or) E Vs Brillouin zone.

2. Is the Brillouin zone plotted in X axis and the k points are same or not???

Your reply is highly appreciated in advance.

Title: Re: Band structure Energy
Post by: Petr Khomyakov on May 14, 2019, 13:24

Please could you clarify your questions?

Title: Re: Band structure Energy
Post by: GJK on May 17, 2019, 10:50

Hi,

1. Once we generate band structure through our quantum ATK we get a plot between Energy  E and Brillouin zone route(attachment given). The Fermi level EF is normalized to zero. The y-axis says its energy E.The question is that -in the y-axis is it E-EF plot or just E with Fermi level alone being normalized to zero.

2.

Title: Re: Band structure Energy
Post by: GJK on May 17, 2019, 10:56

2. In the X-axis plot of band structure, we have the Brillouin zone route specified for each material. Is that the k points???

Because specifically if we draw E-k diagram do we need to replot the band structure or what ATK provides us user-friendly E Vs Brillouin zone route is the E-k plot??? Certain tutorials of yours also claim it as E-k plot. Your valuable reply is highly appreciated.

Regards
Jananikumar

Title: Re: Band structure Energy
Post by: GJK on May 17, 2019, 11:59

Band structure for question 1

Title: Re: Band structure Energy
Post by: Jess Wellendorff on May 20, 2019, 14:16

It is very simple: The band structure plot is Energy vs. k-point position in the BZ, so the x-axis is a route in the BZ. The y-axis is Energy referenced to the Fermi level, so -2 eV means the energy is 2 eV below the Fermi level. Just a standard band structure plot.

Title: Re: Band structure Energy
Post by: GJK on May 30, 2019, 12:21

Hi,

But is the Fermi level alone is normalized to zero? The rest values in Y axis is only energy E and not E-Ef.

Am I correct?

Title: Re: Band structure Energy
Post by: GJK on May 31, 2019, 16:38

What does "Energy Referenced to the Fermi Level means"-
 
1.Is it  Fermi level alone normalized to zero??

2.The other Energy values lying above and below the Fermi level are just E or is it E-EF???

Kindly clarify

Title: Re: Band structure Energy
Post by: Petr Khomyakov on June 1, 2019, 09:15

1. Yes, the Fermi energy is set as zero energy. In general, the absolute energy is not uniquely defined, because the electrostatic potential that is defined up to an additive constant.

2. E is the energy as it comes out of calculations. E-E_F is then the newly-defined energy when the Fermi level is shifted to zero.

Title: Re: Band structure Energy
Post by: GJK on June 1, 2019, 16:49

Hi,

You mean above and below EF(which is normaized to zero) in the Bandstructure plot the energy values are plotted as E-EF in the y-axis???

Title: Re: Band structure Energy
Post by: Petr Khomyakov on June 1, 2019, 21:31

If the Fermi level is at zero. It means above or below zero in the plot.