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Thank you for your clear explanation

Thank you sir

Dear Prof. Alexandru, Thank you for sharing the informative video. It arrived at the perfect time as I'm currently investigating the stability of defect clusters in wustite. I'm particularly interested in applying convex hull analysis to this study. I understand that this topic isn't extensively covered in textbooks, and I believe a deeper understanding of convex hull application would be invaluable to my research. Would you be able to share some resources on this subject? Thank you for your time and consideration. Best, Emmanuel

I have a conceptional question. Lets say I am studying a material which contains A and B , and A in its pure form is fcc and B is hcp . By this I mean, that a total energy for A is minimal for the crystal structure fcc , but for B it is hcp . The formation energy you defined is the total energy of A_n B_m minus n * atomic energy of A minus m * atomic energy of B. First question : What reference atomic energies do I choose ? From my understanding I have to perform a energycalculation for fcc A bulk, divide it by the number of atoms. And for the other element , I perform energy calculation for hcp B bulk. Is this right ? The second issue : Consider that I calculate the total energy of A_n B_m for the whole composition space, but only for one crystal structure. This is not the convex hull , right ? In fact, I have to calculate for all possible crystal structures the total energy over the whole composition space . However this is way to expensive. So is there a way to improve this calculation? In other words, if I know pure B is hcp , and pure A is fcc, then probably I dont have to run a calculation with fcc A_n B_m compound for large amount of B . But how to set the limit ? For this I would have to know all the possible phases..

Nice presentation Professor, please make a separate videos on Mott insulator and Mott Hubbard insulator and its correspondence with high temperature supercomputer. That will be very helpful, since your skills of explaining complex things are really good.

Thank you very much. Indeed very helpful. Also, would love to explore your group.

Thank you for this video! I understand what's happening in a convex hull plot and how they did it now 😁

Very well done presentation on the topic!

Wow! You sold your lab, the department, the school and the state in one 7 minute presentation: AWESOME!

Great

Ah, typos sorry: at 4:40 E_AB should be E_A3B. At 5:19 should be lowest energy structure for given stoichiometry.

Thanks for inspiring me. I am one who are looking for a position. It useful.

Thank you very much. This is quite insightful.

Papers: 1) www.nature.com/articles/s41563-020-0757-x 2) www.nature.com/articles/s42005-022-00909-z 3) www.science.org/doi/full/10.1126/science.aam9189?casa_token=_qrFmIhH4FAAAAAA%3AEYwXabiM-hPgXqtRbuF_k1Ug3NQOSC-Jt3Gp8_LnKtjlF-_Fn3bg46rcoCVrAEzH-Rx7uw9HA8Ut9y4

Timestamps: 0:00 Intro 1:30 Layered Structures of 2 MIT materials 2:30 Bulk RNO Physics 03:54 Layered RNO Materials 05:09 First Order Phase Transitions 06:50 Electronic and Lattice Mismatch 07:34 Order parameter in the superlattice 09:20 Experimental confirmation of theory 09:49 VO2 Superlattices - metastable states 10:40 Electronic and lattice switching 10:57 Computation: electronic and lattice disentangling

0:00 Intro from Tyrel McQueen 0:25 What you should get from this talk 1:40 Correlated Electron Materials in a Nutshell 2:45 Flat Bands: Kagome and Moire 3:45 Type 1 vs 2 Superconductors 4:30 Mott Physics 6:25 Electron or lattice physics? 7:00 Mott insulator 8:50 Correlated Metals 9:30 DFT vs ARPES in correlated metals: Hubbard bands and quasiparticles 10:35 DMFT, Subsidiary Bosons 11:02 DMFT Spectral function NdNiO2 and CaCuO2 11:55 Self Energy 14:45 Self-Energy and Spectral functions in SrVO3 15:03 FermiSee, simple Fermi Liquid Tool 15:57: p-d models intro 22:50 things to keep in mind when reading DMFT papers 23:30 local ionic environment and effective models 25:22 Tune Tc in cuprates via apical oxygen 27:26 Nickelate and cobaltate heterostructures for superconductivity 30:29 Machine Learning Status

Thank you for such an interesting video. Your students are lucky.

Welcome! This video is meant to explain a few key concepts I've found useful: I discuss Peierls distortions, hydrogen molecules, why antibonding orbitals destabilize materials, Bloch wavefunctions, p-d models versus low-energy models, Wannier functions and the LCAO (linear combination of atomic orbitals) approximation. I was inspired to make this video by Nobel Prize Winner's Roald Hoffman's Book ''Solids and Surfaces: A Chemist's View of Bonding in in Extended Structures", as well as by concepts I found useful in my own work (a lot of Wannier functions and p-d models). I am thankful for suggestions for this video from Jennifer Fowlie and Julia Bauer. The two papers I reference from my own work are: 1) What causes electron vs lattice symmetry breaking: www.nature.com/articles/s4200... 2) TiCl2 Wannier function, and more generally trigonal symmetry in 2D halides: journals.aps.org/prb/abstract... You can also check out my website: www.alexbgeorgescu.com/ or follow me on twitter: twitter.com/AlexandruBG

0:34 1D chain and Peierls Distortion 1:20 Hydrogen Molecule: bonding and antibonding 2:20 Hydrogen Molecule: bonding stabilizes, antibonding destabilizes structure 2:55 Bloch States as states in a very long molecule 5:22 Supercells and Band folding (in the context of the Peierls distortion) 7:18 HOMO/LUMO and top valence band/bottom conduction band 7:55 p-d model and bonding and antibonding 10:30 p-d model vs antibonding only models; Density of states and projected density of states 12:53 antibonding low energy model vs p-d model in the rare-earth nickelates 13:38 LCAO (linear combination of atomic orbitals) and Wannier models 14:43 Wannier models 15:22 Wannier models: p-d and antibonding. 15:50 Thank you and other videos/subscribe