Dear Zara:

 In addition to Leonardo’s answer, you can take a look to these papers:

 
Band alignment at metal/ferroelectric interfaces: insights and artifacts from 
first principles 
Massimiliano Stengel, Pablo Aguado-Puente, Nicola A. Spaldin, and Javier 
Junquera 
Physical Review B 83, 235112 (2011)  
<http://dx.doi.org/10.1103/PhysRevB.83.235112>[ cond-mat/1103.0504 
<http://arxiv.org/abs/1103.0504>] 

First-principles calculation of the band offset at BaO/BaTiO3 and SrO/SrTiO3 
interfaces 
Javier Junquera, Magali Zimmer, Pablo Ordejón, and Philippe Ghosez 
Physical Review B 67, 155327/1-12 (2003)  
<http://dx.doi.org/10.1103/PhysRevB.67.155327>[ cond-mat/0210666 
<http://xxx.lanl.gov/abs/cond-mat/0210666>] 

Hope this helps,

 Javier



> El 13 oct 2017, a las 22:17, Leonardo Fonseca <[email protected]> 
> escribió:
> 
> Dear Zara,
> 
> In general you cannot obtain the barriers directly from the atomic 
> potentials. The barriers you are talking about are between band edges, either 
> a Fermi level/conduction band alignment or a conduction band/conduction band 
> alignment when you are dealing with metal/dielectric or dielectric/dielectric 
> interfaces, respectively. The stack potential is the reference energy against 
> which you will find where the band edges (or Fermi level) are. You can either 
> combine bulk calculations of each material combined with your interface 
> calculation to obtain the location of the interface band edges (see Van 
> deWalle, C.G., Martin, R.M.: Theoretical calculations of heterojunction 
> discontinuities in the Si/Ge system. Phys. Rev. B 34, 5621–5634 (1986)) or 
> you can plot a layer-by-layer PDOS which will give you the band alignment 
> directly. Each method has its own limitations, so to be sure it is better to 
> do both.
> 
> I hope this helps.
> 
> Leo
> Center for Semiconductor Components
> University of Campinas, SP Brazil
> 
> 2017-10-13 12:24 GMT-03:00 Zara Nosh <[email protected] 
> <mailto:[email protected]>>:
> Dear expert,
> 
> In the resonance tunneling devices (RTD), there are 2 potential barriers 
> inside the conductor. My system shows NDR behavior in its IV curve and it 
> seems that it is  a RTD system.
> I have plotted the voltage drop profile, ElectrostaticPot(V) 
> -ElectrostaticPot(0), however I couldn't find barriers.
> 
> How can i visualize the potential barriers in my system?
> 
> Also I don't know in which bias I have to look for the barriers? In the peak 
> or somewhere between peak and valley, or maybe everywhere it should be 
> appeared? 
> 
> I really appreciate your help.
> Best wishes
> Zara
> 

AAA

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