Recent content by Douasing

In VASP, there is a parameter called NBMOD as follows: NBMOD=0 : Take all bands to calculate "the charge density", even unoccupied bands are taken into account. NBMOD=-1: Calculate the "total charge density" as usual. This is the default value if nothing else is given. What's the difference...

Why is black phosphorus a semiconductor with a direct bandgap? The problem is mentioned by the two following references: "The three bonds take up all three valence electrons of phosphorus,so, unlike graphene, monolayer black phosphorus is a semiconductor with a predicted direct bandgap of 2 eV...

In fact,that would solve the problem only if the "ulimit -s unlimited" is used. And "how much memory is used" is closely related to the stack size.

For violet phophorus,it seems that the crystal structures given by two websites are not the same.In Openstax CNX,the link is http://cnx.org/contents/f46e8679-ee00-4073-9f5e-a87ca9955a9e@25.9:67/Chemistry_of_the_Main_Group_El and the Figure 12 displays it as follows: But in Chemwiki,the link is...

Of course. The link is http://journals.aps.org/prb/pdf/10.1103/PhysRevB.78.235430 And the FiG.3 is shown as follows: FIG. 3. Color online Band decomposed charge density at the Gamma point for 13,0, 14,0, and 16,0.

Hi,there are many literatures concered with band decomposed charge density(As an example,see FIG.3 in PHYSICAL REVIEW B 78, 235430 2008). For condution band,there should not be charges or electrons when the system is in the ground state,but,those literares still show a band decomposed charge...

There are many DFT(density functional theory) related softwares,for example,VASP,ab initio,DFTB,ELK,WIEN2K,and so on. Which one do you use? What are the advantages and disadvantages of these first principle softwares in your opinion?

Thank you for your suggestions. But I find some vitual frequency when use phononpy and vasp to calculate the phonon of black phosphorus nanotubes (about 32 atoms for armchair PNT with n=8,see the figure below).On the other hand,it is very time consuming when use Elk-code (about 5 days for 4...

Is there a simple and convenient way to estimate the electron mobility ? I can derive the m^* from band structure data ( through curve-fitting and then take a derivative with respect to k-point),but I know little information for the scattering time ;how to estimate \tau for the systems (for...

What do you mean? Is there any direct relationship between "how a weak periodic potential gives rise to a bandgap" and "where a band gap is" ? In many cases, the band gap is indeed not at the high symmetry points or located in the boundaries of the Brillouin zones (using vasp or wien2k, for...

That makes me think of a very interesting cartoon called "Horton Hears a Who!" (by Theodor Seuss Geisel). I have ever seen the movie twice and thought about its significant carefully. Especially,I often dissolved in tears when I heard the voice "We are here! We are here!" from the speck of dust...

Here is a question making me feel puzzled. Actually,I don't know very clear why 4*4*4 might be good enough for insulator,especially for atomic or molecular system,generally, 1*1*1 is enough. For k points (lowercase,k),it should perform the periodic boundary condition. In my opinion,the...

Thanks for your supplied information.I have ever seen the other web address(i.e.,segmentation fault after 5 iterations) in vasp support site. But, my INCAR is very simple,just a single atom system. Even though,when I change ENCUT=240 to ENCUT=300,the vasp.5.2 can't work. I asked some...

Dear all, There is a “error report” when I use “mpirun” to run vasp.5.2 (a kind of DFT software) as follows: "mpirun noticed that process rank 2 with PID 16380 on node wangtc exited on signal 11 (Segmentation fault)." I can't solve it all the time,can anyone help me ? Thanks...

Yesterday (May 16，Friday) was the birthday of Maria Gaetana Agnesi. Sincere blessing to Agnesi.