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exercises:2017_ethz_mmm:bands_1 [2017/05/10 09:56] – dpasseroneexercises:2017_ethz_mmm:bands_1 [2020/08/21 10:15] (current) – external edit 127.0.0.1
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 +======Crystallographic point groups, free electron model======
 +
 +
 Starting from 2006 Hafnium silicates replaced SiON as gate oxide Starting from 2006 Hafnium silicates replaced SiON as gate oxide
 in MOSFETS. The high dielectric constant of HfO2 and the ability in MOSFETS. The high dielectric constant of HfO2 and the ability
 of HfO2 to form silicates played a key role in the industrial transition. of HfO2 to form silicates played a key role in the industrial transition.
  
 +<note important>
 +connect to hypatia:
 +<code>
 +ssh -X EMPA-USER@jump1.empa.ch
 +ssh -X hypatia
 +</code> 
 +<code>
 +module load povray
 +module load python/2.7.12 
 +</code>
 +
 +go in the directory where you want to put the exercise and do:
 +<code>
 +cp /home/cpi/exercise_10.tar ./
 +tar -xvf exercise_10.tar
 +cd exercise_10
 +</code>
 +
 +
 +</note>
 +
 +
 +====Task1====
 <note warning>Follow the instructions contained in the ASE webpage dedicated to spacegroups <note warning>Follow the instructions contained in the ASE webpage dedicated to spacegroups
  
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 [[https://journals.aps.org/prb/abstract/10.1103/PhysRevB.65.233106]] [[https://journals.aps.org/prb/abstract/10.1103/PhysRevB.65.233106]]
  
-all data necessary co construct the monoclinic phase of HfO2+all data necessary to construct the monoclinic phase of HfO2
  
 </note> </note>
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 modify the python script hfo2.py according to your needs. modify the python script hfo2.py according to your needs.
  
-Execution of the python script will open ASE visualizer showing you the structure,+(replace "...") 
 + 
 +Execution of the python script  
 +<code> 
 +python hfo2.py 
 +</code> 
 + 
 +will open the ASE visualizer showing you the structure,
 will produce the file hfo2.xyz, hfo2.png and hfo2.pov will produce the file hfo2.xyz, hfo2.png and hfo2.pov
  
 to create a "nice" image of the primitive cell you can render the output file hfo2.pov with the command to create a "nice" image of the primitive cell you can render the output file hfo2.pov with the command
 +<code>
 povray +W320 +H320 -I./hfo2.pov -Ohfo2 +P +X +A +FJ +C povray +W320 +H320 -I./hfo2.pov -Ohfo2 +P +X +A +FJ +C
 +</code>
 or executing the script or executing the script
-./povray.sc (that will take care of removing files hfo2.jpg and hfo2.inc)+<code> 
 +./povray.sc  
 +</code> 
 +(that will take care of removing files hfo2.jpg and hfo2.inc)
 </note> </note>
  
 <note warning> <note warning>
 -how many atoms are contained in the unit cell? -how many atoms are contained in the unit cell?
 +
 +-compute the volume of the unit cell
 </note> </note>
-Have a look at the atomic coordinates, for example in the file hfo2.xyz and try to reproduce them, starting from the+ 
 +====Task2==== 
 +Have a look at the atomic coordinates, for example in the file hfo2.xyz (where you also find the cell vectors in cartesian coordinates) and  
 +<note warning> 
 +try to reproduce them (just the 4 Hf atoms), starting from the
 coordinates that you find in the article and applying the symmetry operations of the space group: coordinates that you find in the article and applying the symmetry operations of the space group:
  
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 4)x,-y+1/2,z+1/2 4)x,-y+1/2,z+1/2
 +
 +**DO NOT FORGET Periodic Boundary Conditions!!** but it's simple: x,y,z are given in crystal coordinates so, if for example x=0.276
 +for "-x" you can use -x+1 = 0.724
 +
 +</note>
 <note important> <note important>
-usually teh coordinates are provided in crystal coordinates so+usually the coordinates are provided in crystal coordinates so
 if a1=(a1x,a1y,a1z),a2=(a2x,a2y,a2z),a3=(a3x,a3y,a3z) are the three basis vectors of the crystalin cartesian coordinates if a1=(a1x,a1y,a1z),a2=(a2x,a2y,a2z),a3=(a3x,a3y,a3z) are the three basis vectors of the crystalin cartesian coordinates
 and (x1,y1,z1) will be the crystal coordinates of atom 1, the cartessian coordinates of atom 1 will be: and (x1,y1,z1) will be the crystal coordinates of atom 1, the cartessian coordinates of atom 1 will be:
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 </note> </note>
  
 +
 +====Task 3====
 Check the lecture notes for the free electron model and: Check the lecture notes for the free electron model and:
 <note warning>Compute the Fermi energy (in eV) and the Fermi wavevector (in cm-1) for Cu,Au,Ag </note> <note warning>Compute the Fermi energy (in eV) and the Fermi wavevector (in cm-1) for Cu,Au,Ag </note>
 +
 +
 +====Task 4====
 Have  a look at this ASE page to compute bandstructures and the symmetry points of the Brillouin zone of a crystal: Have  a look at this ASE page to compute bandstructures and the symmetry points of the Brillouin zone of a crystal:
  
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 Compute the free electron bandstructure of Si and Cu Compute the free electron bandstructure of Si and Cu
 (Have a look at the scripts included in the exercise directory) (Have a look at the scripts included in the exercise directory)
 +
 +Write the CARTESIAN COORDINATES of the Gamma, X, W points of FCC
 </note> </note>
  
exercises/2017_ethz_mmm/bands_1.1494410179.txt.gz · Last modified: 2020/08/21 10:15 (external edit)