Graphene Definition and 212 Threads

Basically, I've written some code that take as inputs 1)Basis vectors 2)lattice translation vectors and computes the structure factor of the basis, producing a diffraction pattern. I'd like to begin incorporating subtle differences between atoms, so I want to compute the structure factor of...

Copper conducts electricity and so does other metals like silver. Now a new material is coming to play which is graphene, But I was wondering in order to generate electricity must it be in copper coils? Can it be in silver coils, graphene coils? ^.^

Dear All, I have three questions about the relation between the K-points and energy cutoff. The first one is : how many k points should I use in my theoretical calculation to get a good result in lattice constant and the converge of Emin especially for using DFT? The second one is : What is...

A lot of people have been arguing that TSLA's stock/the company in general won't take off because the demand is above the battery technology at this time. I'm a junior in college studying physics but will probably either switch to finance and do stocks because i like it more or i was double...

I'll just launch into it: I graduated recently from Temple University with a B.S in Physics, GPA 3.83. I worked in three labs, one semester each, during my studies: one for pay, one volunteer, and one for credit. In the first, I did analysis for Mossbauer spectroscopy; in the second, I produced...

Homework Statement Using the dispersion relation at the Dirac Point calculate the electron density of states for graphene in both the valence and conduction band. Homework Equations ρ = density of states = k2/pi2 The Attempt at a Solution I looked up what Dirac Points...

Hi All, I'm finishing up my PhD in Computational Condensed Matter. I've worked almost exclusively in spin systems using things like Monte Carlo and Exact Diagonalization. However, my specialty is in producing high-quality, high-performance, often parallel research codes (i.e. none of my...

Hello, I started this topic to discuss interesting new night vision technology that was presented on TED talks. Old, expensive and bulky IR (or other light spectrum) IIT amplifier could be replaced with very thin OLED based, cheaper and low power consuming image intensifier which was developed...

Hey everyone, I'm currently doing research at a University, I've been working on a problem for a few hours and wrote up a quick paper that shows my derivation of a certain height based on an angle. Basically the experiment is looking at optical properties of graphene, but for this to happen we...

Ok so I have a view ideas in mind for a project I was planning on doing involving genetic algorithms for my high school science fair class. I do have 3 mentors one a mathematician, a computer scientist who focuses on GAs, and a physicist who focuses on nano structures. here where I live, but...

Recently, reading an article about graphene, it was disclosed that a sheet of graphene the thickness of a piece of plastic wrap could support the weight of an elephant balanced on a pencil. Beyond the fact that I highly doubt anyone got an elephant (although good at balancing tricks I have seen...

Hello, I'm interested in research and development of either fusion power generation or graphene based nanoelectronics. One of the things I like about these areas is that they are in the imminent stages of development and I will probably see them developed in my lifetime. My issue is that...

Can we make exoskeletons out of CNTs? I have a few questions 1. Do CNTs expand when electricity is applied or you have to put wax betwen them? 2. Can we produce enough nanotubes to make a full-body suit? 3. Is graphene suitable for an armor? Some say that when you put a elephant on a...

I've gotten really interested in CFD and DFT recently. I have a BS in Chemical Engineering and will be 25 in about a month. Been working in the oil industry for the last 2 years and before that I worked in a carbon nanotube and graphene 'factory' for lack of a better term that I can come up with...

Hi everyone, I'm trying to fit the Tight Binding molecule for a more complicated system, so I'm first trying to understand it for a simpler one, graphene. I've read several guides but they're all confusing me. Right now, I'm trying to understand the graphene example on this site. My biggest...

The theoretical "Augmentations" One thing that is somewhat common and has to do with medical science and my interests are augmentations, robotic, nano-technological, or even sometimes genetic enhancements. In the science fiction representations people can outperform human strength and speed...

I have read many papers stating that the wave function of graphene has two components due to the fact that the unit cell of graphene consists of two carbon atoms (A and B atoms). However, I was confused about that. If the unit cell consist of more atoms, what will the wave function be? Does it...

The Brillouin Zone (BZ) of both graphene and the (111) surface of metals like Ag(111) eihibit a hexagon, but I wonder why the BZ of graphene has two inequivalent ponits K and K', while the K point of BZ of the Ag(111) is equivalent. Thank you in advance!

Who can explain the following questions about transfer matrix? formula (31) in New Journal of Physics, Vol.12 123020. [http://iopscience.iop.org/1367-2630/12/12/123020/pdf/1367-2630_12_12_123020.pdf] is different from the result of another paper in Journal of Physics:Condensed matter...

Hi, I'm reading a paper (please find it here arXiv 1003.2193v1) on zigzag Graphene nanoribbon (ZGNR). It discusses the electron transmission through a p-n interface. The wave function matching method was employed to calculate the transmission. What I don't understand is as follows: In...

Dear all, My aim is to get the density of states (DOS) per unit area for monolayer (bilayer) graphene. I have done this using mathematica. I have set a sampling k grid with 22500 points and computed the expression: DOS=(1/Nk)*Ʃ δ(E-Ek) where the sum is over the k points in the reciprocal...

Researchers used a DVD player to burn graphene oxide into graphene, demonstrating a very simple new method of fabrication: http://www.rsc.org/chemistryworld/News/2012/March/graphene-dvd-player-burn-supercapacitor.asp

Hello everyone; I have been working in a research group whose aim is to develop and making graphene-based nanoelectronic device. http://labs.sabanciuniv.edu/qtnel/ I am undergraduate student that's why I could be considered source of this laboratory by making mechanically exfoliated graphene on...

Graphyne is a variant of graphene which has Carbon-Carbon triple-bonds: http://physics.aps.org/articles/v5/24 Image: I'm thinking that it wouldn't have superior mechanical properties, since the presence of the triple bond would give a polar character that weakens the SP2-hybridization...

Hi guys, I am currently writing my dissertation on Graphene and I am investigateing how graphene remains stable, contradicting existing well established theory which states 2D materials cannot exist independently. With the main area of investigation looking at possible lattice distortions...

Just read this article and figured I'd share it: http://arstechnica.com/science/news/2012/01/size-matters-when-things-are-just-right-water-flows-freely.ars However I do have a question. The article never explained why helium, hydrogen, and other gasses were being blocked, they only explained...

http://www.manchester.ac.uk/research/news/display/?id=7895 http://arxiv.org/ftp/arxiv/papers/1112/1112.3488.pdf What kinds of applications can you see this being used in and how soon?

I've read several not-very-scientific articles about graphene. What puzzles me is this: It is supposed to be a one-atom-thick layer of carbon atoms, and it is claimed that it could work as a display (like a very flexible screen or something like that). First of all, how would we be able to see...

If one had a large sheet of graphene (as in square meters--but not necessarily a monolayer sheet) which was then puctured/torn by a blade, how would the tear react to lateral tension parallel and perpendicular to the tear? Would it "unzip" easily under perpendicular tension, or would the...

Well I don't read much into this subject on graphene.But i have read there are obstacles to over come... much like quantum computers which have probably a million times more complicated issues to over. I'm skeptical that a quantum computer will exist in the home for 100+ years... But will...

How does it come that graphene is so strong, but not graphite? Graphite is basically just many graphene sheets stacked on top of each other so it should super duper strong.

I am currently looking at what research groups to apply to for starting a PhD next year, is there anywhere particularly good that I am missing out? I did my Masters in Theoretical Physics but I am actually leaning more towards a mixture of both experimental and theory at this stage, I did do...

How do I go about deriving the thermal conductivity of graphene (specifically, in the low temperature limit) when I'm given the phonon dispersion relation? I haven't been able to find anything explaining how the dispersion relation relates to the thermal conductivity in materials. (this is...

Hello, I am trying to write a program that will automate the creation of a tight binding Hamiltonian matrix for armchair cut graphene. However, I have almost no experience coding and would need some help to get started. This would be assuming that the energy between nearest neighbor carbon...

hi, I was reading an article about graphene and I came across some concepts I am not familiar with. I was just wondering if someone could help me understand them: The article says that charge carriers in graphene are massless fermions that are described with a Dirac-like equation rather than...

I recently read the paper by Maiti and Sengupta in PRB Vol.76, 054513 (2006). I also read a preprint arxiv:cond-mat/0604594v3 There are inconsistency in these two articles. In the Eq.(10) in the first paper, \psi_B^{h\pm}\propto (0,0,1,\pm e^{\mp i\theta'}) While in the reprint(see appendix...

Hello :) I'm not at all a specialist in condensed matter, nor do I understand much of its basics. I'm nevertheless a 1st year physics student who has a summer project on some aspect of modes in graphene and I would like to understand why the mathematics I was using this summer was the one...

I am wondering if the properties of graphene could have implications for solar sails. I don't know much about graphene but I do know that it is only an atom thick and very very strong and theoretically can be made of infinite size. Are there any problems that graphene would face in terms of...

Hi! Is anyone familiar with generating band structures from DFT simulations? I am using graphene, and am trying to plot the electronic structure at the high symmetry points (K, M, and gamma). Grappling to understand this theory, my questions are: 1. Is the location of the high symmetry...

I was reading all over the place that graphene has some really great electronic properties that could potentially replace silicon, electrons in graphene behave almost like massless particles etc. My question is, HOW did scientists find out these properties in graphene? What kind of experiments...

After considering the thread https://www.physicsforums.com/showthread.php?t=474384 I began to think about the bonding in graphene. As long as we can neglect electron electron interaction, the ground state can be obtained almost trivially in a tight binding approximation. On the other hand...

http://edu.ioffe.ru/register/?doc=galperin/l3pdf2.tex I don't understand how do you get from equation 21 to 22? How did the summations of exponentials becomes cosine functins?

Hi, has anyone had any experience with visibility of single-layer flakes of graphene on substrates with non-optimum thickness of SiO2? We've been shopping for some Silicon wafers with 300 nm of SiO2, but our supplier can only ensure the oxide thickness within 10% of the specified value. I...

I had a task from my supervisor, graphene layer has 2 Carbon atoms per unit cell. What will happen if the atoms are replaced by one atom Boron and one atom Nitrogen? Will we found an open band gap? Would you please inform me any literature concerning it?

hı ; Pleaseee help mee. My thesis subject is graphene ribbon and Landau Energy Bands of Graphite. I am trying to plot graphics in energy levels of tight-binding electrons in graphane in the presence magnetic field but I couldn't plot graphic exactly .Can you give me information how I can draw...

I am reading about the electron flow in graphene and the article said this "This behavior is not described by the traditional mathematics (Schrodinger equation) but by the mass-less Dirac equation" What does this mean and what is the massless Dirac equation... the whole paragraph is...

I plot the tight binding bandstructure of graphene. There is a very good aggrement with ab-inition calculation in the valence band. but there is a problem in the non-localized orbitals of conduction band especially in the Gama(0,0) point. Any suggestion is appreciated.

Greetings, I'm looking for a way to calculate the molecular harmonics of a sheet of graphene. Any suggestions or tips would be greatly appreciated. How to approach this task with a hexagonal lattice and using atomic-scale objects leaves me stuck wondering how to do it. Wiki briefly describes...

Hi folks, I am desperately trying to understand how this device is working... I would like to precise that I understand how field effect transistors/junctions based on p- and n-types semi-conductors are working (with a p-type gate it is ok; with a n-type gate it is already less ok since holes...

Hello , Maybe this topic has basic understandings of quantum mechanics and involves some mathematic theory that I haven’t learned yet, but it’s related on graphene sheet and Klein tunneling . Consider that our observation is so much larger in scale then sub-lattice constant...