How to Calculate Effective Mass using E-K diagram ? - Dr Mohan L Verma

This lecture deals with the simplest method to calculate the effective mass of electrons and holes in semiconductors (direct and indirect band gape both) using the E-K dispersive curve obtained through any DFT tools (Here I am using SIESTA). Before watching this one should have a preliminary idea of effective mass and its derivations available in any solid-state physics book. Enjoy learning.

[@binodregmi7386]

Thanks sir for your explanation. It looks like we need to convert k axis by (2*pi/a) because numerator quantity is in the real space. The value of K need to be in real space rather than reciprocal space.

[@shavkatmamatkulov2333]

Sir, thank you very much! Great explanation.

[@siestaindiahandsontutorial5627]

Thanks a lot...

[@joysarkar4675]

Great technique.. thank you sir

[@siestaindiahandsontutorial5627]

Most welcome 🙏

[@shwetaagrahari1001]

I have got an issue to install siesta software in which there is found some error 'mismatch file' how to resolved this process....plz reply back sir🙏🙏🙏🙏🙏

[@eddyodondo1620]

Thank you sir for this knowledgeable lecture. Please suggest me how can we calculate the effective mass along any direction like along x-axis, y-axis?

[@siestaindiahandsontutorial5627]

One separate talk is uploaded in this channel for effective mass calculation

[@anilkumarsingh9398]

Sir, Thank you for this informative explanation on effective mass. I have also tried for my system using Xmgrace with the bandstrucutre obtained using Quantum espresso, which is a vdW heterostrucutre with hexagonal symmetry. But I found very strange values, which is very very larger than the rest mass of electron though tried many times with different number of points at CBM as well as VBM. Can you suggest some way to get rid of this error? Is this method is applicable for any crystal symmetry or not?

[@siestaindiahandsontutorial5627]

What is the value you obtained? Send me your band plot if possible

[@user-wj7ik3cp6x]

how can you calculate for non-parabolic fit

[@siestaindiahandsontutorial5627]

Then check the calculation. And physics behind E-K plot

[@physicschanneldz1707]

Shouldn't k-axis be multiplied by 2pi/a? so that the values of k are in (1/Ang.)

[@pedrosouza1961]

In the correct case, we would make a division of A0 per 4pi^2 if the band is plotted using the vasp. What do you think?

[@rushikeshjadhav6637]

I have simulated a band structure where along the X-axis, the points are defined using the 3 dimensional k-paths (Gamma, X, etc.). Does it mean when I am curve fitting E-k plot, I will have to separately take kx, ky and kz and then find the effective masses along the three axes? What should be done here? I am confused.

[@siestaindiahandsontutorial5627]

You can calculate in any direction ...

[@anishalamba5844]

@@siestaindiahandsontutorial5627 thankyou sir for this knowledgeable lecture. Please suggest me how can we calculate the effective mass along any direction like along x-axis, y-axis? Is this method same for isotropic system and anisotropic system?

[@amalyassin6900]

Dr i want to find Band structure and DOS for carbone nanotube( in his 2 types). So i have to FdF File. Know you any Website or tutorials for this project?!

[@siestaindiahandsontutorial5627]

Use this technique for the same...

[@billclintone9701]

​@siestaindiahandsontutorial5627 How do I get the anisotropic effective mass along x, y and z directions

[@marwahaouam6720]

I did the same again, but I got A0= 3.68662 instead of A0= 11.5198. Why didn't I get your result ?

[@siestaindiahandsontutorial5627]

Try again with lil bit careful by selecting points ...I have checked my result several times ....

[@physicschanneldz1707]

@@siestaindiahandsontutorial5627 Shouldn't k-axis be multiplied by 2pi/a? so that the values of k are in (1/Ang.)