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papers [2019/03/04 13:33] – janettatepapers [2019/03/04 13:45] – janettate
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-====== Poster and paper assignment ====== +====== DFT project ======
- +
-DFT project+
  
 One of the goals of the course is to become familiar with modern computational software that solve difficult problems in solid state physics. You will use the software package OpenMX to calculate the band structure of a semiconductor, metal, or insulator. You can complement your own calculations by downloading band structures from an open source project called aflow. Decide on an interesting system (talk to the instructor and others about what is feasible). You always start by reproducing the work of others, and then go on to explore by yourself. You will calculate (at minimum for a passing grade) the dispersion relation and the total and partial densities of states of an interesting material. You will also calculate at least one other property – electron density, optical properties, spin polarization etc., for a B or higher grade. The difficulty of the project will be taken into account in assigning the grade. One of the goals of the course is to become familiar with modern computational software that solve difficult problems in solid state physics. You will use the software package OpenMX to calculate the band structure of a semiconductor, metal, or insulator. You can complement your own calculations by downloading band structures from an open source project called aflow. Decide on an interesting system (talk to the instructor and others about what is feasible). You always start by reproducing the work of others, and then go on to explore by yourself. You will calculate (at minimum for a passing grade) the dispersion relation and the total and partial densities of states of an interesting material. You will also calculate at least one other property – electron density, optical properties, spin polarization etc., for a B or higher grade. The difficulty of the project will be taken into account in assigning the grade.
-Poster assignment 
  
-Poster assignment+===== Poster assignment =====
 Summarize your results as a poster to be shown during class (date will be posted on the main calendar of the course). This is a conference of your peers, and may also be attended by interested parties such as former and prospective PH575 students, and faculty. OSU Student Media Services, located in the Valley Library, print posters for free if it is a class assignment. A typical poster size is 3 feet wide, 3.5 - 4 feet tall. Text and diagrams should explain your calculations, and provide other information about your material. During the poster session, you'll stay with your poster for 50% of the time, and circulate around other posters for 50% of the time. Summarize your results as a poster to be shown during class (date will be posted on the main calendar of the course). This is a conference of your peers, and may also be attended by interested parties such as former and prospective PH575 students, and faculty. OSU Student Media Services, located in the Valley Library, print posters for free if it is a class assignment. A typical poster size is 3 feet wide, 3.5 - 4 feet tall. Text and diagrams should explain your calculations, and provide other information about your material. During the poster session, you'll stay with your poster for 50% of the time, and circulate around other posters for 50% of the time.
  
-Paper assignment+===== Paper assignment =====
  
 After the poster session, you will write a paper that describes your findings. The feedback you get from the poster should help you write a better paper. After the poster session, you will write a paper that describes your findings. The feedback you get from the poster should help you write a better paper.
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 If you have questions, please ask! I will almost always email the whole class with my answer, or post the answers here under FAQ. If you have questions, please ask! I will almost always email the whole class with my answer, or post the answers here under FAQ.
  
-Paper/poster FAQ+ 
 +===== Paper/poster FAQ =====
  
 Audience? Audience?
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 Here is non-comprehensive list of materials that people have chosen in the past. Here is non-comprehensive list of materials that people have chosen in the past.
-Do students from previous years have useful advice for me?+xx 
 +yy
  
-Yes! Here is the advice from previous years. 
-What is a CIF file 
- 
-The Crystallographic Information File (CIF) is the standard for crystallographic data exchange prescribed by the International Union of Crystallography . It was described in a paper in Acta Cryst. (1991). A47, 655–685 by S. R. Hall, F. H. Allen and I. D. Brown. 
- 
-Here is some of the text from a CIF file describing anatase TiO2: 
- 
-_atom_site_label 
-_atom_site_type_symbol 
-_atom_site_fract_x 
-_atom_site_fract_y 
-_atom_site_fract_z 
-_atom_site_occupancy 
-_atom_site_U_iso_or_equiv 
-Ti1 Ti+4 0 0 0 1 0.0 
-O1 O-2 0.2821 0.2821 0 1 0.0" 
- 
-Translating the above code into english: “There is a Ti atom at (x,y,z) = (0,0,0) and an O atom at (0.2821a, 0.2821b, 0), where a and b are unit cell dimensions. 
- 
-It is helpful to drag a CIF file into the OpenMX Viewer (a browser based application) to see the crystal structure. You may wish to export the crystal structure as an .xyz file so that you have the actual atomic coordinates. 
-Can I try grading someone's paper from a previous year? 
- 
-Yes. Ethan has copies of papers from previous years. However, you cannot do your paper on the same material that you read about in someone else's paper. 
-Collaboration or no? 
- 
-Teach each other about how use the OpenMX basics. Share tips on how to use the software, especially on how to get to the DoS and the E(k) plots. This just like being in a lab where you show someone how to use a piece of equipment. This kind of collaboration is healthy, but don't do the work for the other person. In a lab, you show someone a tool and he or she decides what experiment to do with it. 
  
 Talk to others to help point you to information, but don't let the other person do all the legwork for you, and likewise, don't do the legwork for others. Talk to others to help point you to information, but don't let the other person do all the legwork for you, and likewise, don't do the legwork for others.
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 Don't work together to construct your posters - the temptation to produce the same format is very strong. This is your poster. But critique someone's poster and offer advice if asked. Tell each other where to get poster materials or how to get access to good printing etc. Don't work together to construct your posters - the temptation to produce the same format is very strong. This is your poster. But critique someone's poster and offer advice if asked. Tell each other where to get poster materials or how to get access to good printing etc.
 +
 Length of paper? Length of paper?
  
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 Why a poster as well as a paper? It's so that you can share your work with the other students and learn something from them, too.  Science is about communicating ideas and results, so you need to practice that.  So come up with something interesting to tell your peers. Why a poster as well as a paper? It's so that you can share your work with the other students and learn something from them, too.  Science is about communicating ideas and results, so you need to practice that.  So come up with something interesting to tell your peers.
    
-=== Cautions ===+=== Pitfalls ===
 Don't write a technical manual (“go to this menu, and click this button”). Don't write a technical manual (“go to this menu, and click this button”).
  
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 ===== Questions from class re the project ===== ===== Questions from class re the project =====
 +Do students from previous years have useful advice for me?
 +
 +Yes! Here is the advice from previous years.
 +Q. What is a CIF file
 +
 +A. The Crystallographic Information File (CIF) is the standard for crystallographic data exchange prescribed by the International Union of Crystallography. It was described in a paper in Acta Cryst. (1991). A47, 655–685 by S. R. Hall, F. H. Allen and I. D. Brown.
 +
 +Here is some of the text from a CIF file describing anatase TiO2:
 +
 +_atom_site_label
 +_atom_site_type_symbol
 +_atom_site_fract_x
 +_atom_site_fract_y
 +_atom_site_fract_z
 +_atom_site_occupancy
 +_atom_site_U_iso_or_equiv
 +Ti1 Ti+4 0 0 0 1 0.0
 +O1 O-2 0.2821 0.2821 0 1 0.0"
 +
 +Translating the above code into english: “There is a Ti atom at (x,y,z) = (0,0,0) and an O atom at (0.2821a, 0.2821b, 0), where a and b are unit cell dimensions.
 +
 +It is helpful to drag a CIF file into the OpenMX Viewer (a browser based application) to see the crystal structure. You may wish to export the crystal structure as an .xyz file so that you have the actual atomic coordinates.
 +Can I try grading someone's paper from a previous year?
 +
 Q.  How do I know my band structure is right?  Q.  How do I know my band structure is right? 
  
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 Q.  My material has 80 atoms per unit cell - that OK? Q.  My material has 80 atoms per unit cell - that OK?
  
-A.  80 atoms is too big for our system, but there may be some symmetry that allows a smaller cell to be used and Wien will find it.  So try it and see.  If it's too big, you'll use all the memory and tie up the system so no one can use it.  Not good!  +A.  80 atoms is too big for our system.
  
 Q. Can I study doping, (eg B-doped Si) or solid solutions like ZnS_(1-y)Se_y? Q. Can I study doping, (eg B-doped Si) or solid solutions like ZnS_(1-y)Se_y?
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 Q. Can I study graphene? Q. Can I study graphene?
  
-A.  The 2-d nature of graphene requires special symmetry that is too difficult for a beginning project in Wien.  Graphite is a better choice.  (You might be able to use Flair for graphene, but you must do a 3-d structure in addition to graphene if you go this route.)+A.  We've looked at this material in class, so if you really want to do this, look for a new, related 2D material or try some advanced options.
  
 Q. Can I study conductivity as a function of temperature? Q. Can I study conductivity as a function of temperature?
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 A.  There is an option to include spin polarization, which should allow you to determine whether a material is magnetic or not in its ground state.   A.  There is an option to include spin polarization, which should allow you to determine whether a material is magnetic or not in its ground state.  
- 
-====== 2013 Papers ====== 
- 
-TBA 
  

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