QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: GJK on May 14, 2019, 09:23
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Hi,
1. We are getting bandstruture diagram appearing as Energy Vs Brillouin zone. What does that diagram signify in our software--Is it E-EF 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.
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Please could you clarify your questions?
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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.
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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
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Band structure for question 1
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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.
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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?
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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
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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.
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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???
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If the Fermi level is at zero. It means above or below zero in the plot.