Graphene Definition and 189 Threads

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!

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...

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.

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...

A new conjecture postulates that it may be possible to "create" mass through relativistic effects on leptons inside of graphene, when it is rolled up into a nanotube: http://www.technologyreview.com/blog/arxiv/25914/?p1=A4 Gee, does that imply that it could be possible to manipulate or...

Hi. After i first heard about graphene, a few ideas started forming in my head. but before i can even tell if they would work or not, I need some information on graphene i can't seem to find anywhere else. For one thing its molar mass and another, its physical strength.

Could someone please explain why the thread https://www.physicsforums.com/showthread.php?t=435072"? Not that I have anything against General Physics, but it seems like maybe topics like "Cleaning your PC with a vacuum cleaner", "Rock On Rod Stewart", "My Air Mattress as a Pressure Vessel"...

i am vinoth. i am doing research project related to how we can vary the band gap in graphene nanoribbon and use it to form transistor. now only i started for literature survey related to how we can vary the band gap in graphene nanoribbon.i need some guidance from our friends.i am waiting for...

Researchers have developed silicene, atom-thick silicon sheets similar to graphene: http://www.knoxnews.com/news/2010/aug/25/silicene-new-form-silicon-might-speed-microcircuit/ http://apl.aip.org/resource/1/applab/v96/i26/p261905_s1?isAuthorized=no How similar could atom-thick...

can anyone explain what is d band and g band in the Raman spectrum of graphene?

I have done the computations of band structure of cobalt adsorbed graphene. In 3x3 supercell of cobalt adsorbed (one cobalt atom) graphne, there is opening of band that is gap between conduction and valence band but there is no gap in 4x4 supercell of cobalt adsorbed graphene. I've done this in...

I know that graphene is a far more superb conductor than copper, but I'm trying to compare their weight difference. I mean, let's take an example: A copper busbar that is 7kg with resistance of 2 micro-Ω can carry a lot of current(in kA), I assume a much lighter(possible less than a kg) graphene...

I'm going to see my girlfriend for the first time since the summer began. Any ideas for a nerdy thing to do when I see her or gift to give her? I have access to old, used, crappy graphene if you could think of a way to use that.

Hi, I just read a paper on graphene's basic properties and it says that since current density J is given as J=q*n*v where q is the elementary charge, n is the electron density and v is the Fermi velocity of electrons and for graphene n=6*10^12 cm^-2 and v=10^8 cm/s, the current density...

What is graphene from a physics standpoint? Why do I keep hearing that graphene is considered to be such a major breakthrough? How is graphene going to transform the world?

I'm a third year physics undergraduate and I want to make 3D Graphene - without spending a fortune. This is my background: I found this review article by Jiang and Fan (Design of advanced porous graphene materials: from graphene nanomesh to 3D architectures) to be very helpful. From what...

why do we make composites with graphene oxide not with graphene ? if there is a problem to do composite with graphene ?

Hi. According to the attached article I couldn't draw fig1 with eq1 using mathematica.

All of the sources I have found for this online have been wildly unclear. Many use the phrase "Fermi energy" to refer to the "Fermi level" (which is emphatically not what I'm looking for; I want the Fermi energy as defined in this Wikipedia article: http://en.wikipedia.org/wiki/Fermi_energy )...

Published values for the room temperature thermal conductivity of graphene vary from ~2000 W/m*k to 5600 W/m*k, for freely suspended samples. The large discrepancy shows the sensitivity of graphene to lattice defects (contact with substrate, edge defects, etc.) Thermal conductivity increases...

I've tried searching for it but while there are a lot of hits on the fact that graphene's conductivity is high, there seem to be very few on how the conductivity is actually measured. Would you use the same method as you do with metal wires? Using cross sectional area, length, an ohmmeter...

I had a random idea about the effect of cosmic rays on graphene's conductivity. I found out that cosmic rays would create defects in graphene over time. How many of these defects would significantly reduce the conductivity of graphene? How do I go about calculating how much time the graphene...

I had a random idea and wanted to know whether graphene could retain it's conductive properties after being exposed to cosmic rays. I know that graphene gets it's conductivity from the free electrons from its carbon atoms. I know that cosmic rays consist mainly of protons, with the minority...

Graphene research has been going on for a decade now, with huge numbers of researchers piling into get a cut of the magic. I have a PhD offer in the topic of the mechanical properties of graphene, and I am pondering whether to accept and join the bandwagon myself. I would be interested to...