Recent content by Physicslad78

Dear all, I have a list of pairs say Li={{a,x},{b,y},{c,z}...}. I want to eliminate from this list all pairs that have their second part i.e the x, y, z...>1 and I was thing of using an If loop. Can anyone tell me how please... Thanks...

Hello, In fact I am working with bilayer graphene under the effect of an external voltage. bilayer graphene has 4 bands 2 valence and 2 conduction ones. when u apply a field some excess charge will acuumulate at the 2 layers; I read that this excess charge density is proportional to the...

Dear all, I have a quantum system made up of two layers. An electric field is applied with two voltages applied at both layers. I want to calculate the electronic densities that reside at the two laters in terms of the wavefunctions obtained from solving the HamiltoniaN..Anyone knows of an...

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...

Hi all. Is there any place where I can check how to derive the DOS of bilayer graphene subject to an external field. I have got the Hamiltonian right and solved the eenrgies but then I am not sure how to obtain the DOS right.. Thanks

Hello All I am trying to compile a program and I guess it compiles fine but there is a problem in execution. I get the following error: End of file apparent state: unit 5 (ngh.in) last format: list io lately reading direct formatted external IO Aborted I am not sure what the error...

I am trying to run some calculations on QUANTUM ESPRESSO USING PW.X code. Iam redirecting the input and output files such that: $ /espresso-4.1.2/bin/pw.x <si.scf.in> si.scf.out but what i get is an empty output file in same directory as input file..although in input file I specified the...

Thanks a lot guys. I am trying to reproduce some results.I will try using ESPRESSO.. I am trying to implement the Tight binding model...Is there anywhere I can look at that can help me in doing that? Thanks again

Guys, I have a questiom. Which do you think is better to use when it comes to ab initio quantum calculations the VASP code or the ESPRESSO code. I am a beginner in computational physics and I would like to know the difference. If you can help me in that, I would more than grateful. Thanks

can anyone tell me how to get the real and imaginary parts of the following function : (x+ i y)* Log( a+i b) where x, y a and b are all real numbers and i =sqrt (-1). Thanks very much

Thanks guys for all of your replies.. What I wanted to know is that when does f (-\epsilon) vanish and when it is one. I guess Mute answered the question but he reversed the cases. i tried to plot f (-\epsilon) and found that is it is 1 for \epsilon>-\epsilon_{F} and 0 otherwise. The situation I...

I have a question that is puzzling me as always...The Fermi-Dirac distribution function is (at T=0): f\epsilon=\frac{1}{e^{\beta(\epsilon-\epsilon_{F})}+1} and we know that we can subsitute f\epsilon by 1 for \epsilon< \epsilon_{F} and 0 otherwise. However what is f(-\epsilon)? The answer is...

Thanks very much for explanation...will consult the appendix...:)

Guys, I have two questions: (1) what does a vanishing Fermi energy mean? (2) I have also calculated the phonon self energy for the electron phonon interaction in graphene. However in one of the papers, they state that one needs to subtract from this self energy the case of vanishing Fermi...

Thanks very much for your help. I managed to get the Green functions and drew the Feynman diagrams and discarded the disconnected ones and I got a product of two Green functions of the form G(k lambda , \tau-\tau1)*G(k+q \lambda1, \tau1). where (k \lambda ) is a state of electron with...