Tanmay's Research Blog

Error in routine pw_readschemafile (1): xml data file not found Arises while running band structure calculation This error occurs when bands.in file can not read some data from the nscf run. The files might not be in the correct directory and not have the same filename/prefix etc. Ref:

This error arises while running scf calculation in parallel & solved by putting diagonalization='cg' ; in the input file

Method Step 1 I have taken CIF file (Primitive Cell) for both ZnO & MoS2 from  materials cloud Step 2 Both the CIF file was imported inside VESTA and MoS2 was put on ZnO (10-10) plane by giving the suitable (h, k, l) value (Click here to know how to find it) Step 3 Now to find out suitable scaling In the vertical direction, we have to match the P( perpendicular distance as shown in the fig below) with c of ZnO. In Horizontal direction, In the case of MoS2, the repeating structure is two red stars and the distance between them is found to be 2.42 Angstrom, which we need to match with 'a' of ZnO. When we scale-up MoS2 we have to scale 9 times in horizontal direction instead of 7, since it will be insufficient to cut the MoS2 sheet later but since we are scaling ZnO to be 5 times so we can directly cut MoS2 matching  it with ZnO supercell as below Now we have to cut MoS2 in such a way that it will be periodic at the bounda...

We generally go through a smaller system like 'Si' learn the basics of computational methods, but for our applications in our research, we need to model a more complex system. So I had come across some tools to model systems for Quantum Espresso. 1. VESTA 2. ChemDraw 3. Mercury In some cases also we can use BURAI  to model our system using the modeler tools provided in it. 1.  In  VESTA  we can model different types of solid-state systems including Interfaces. Here are some important tutorials  Supercell construction and adding Vacuum in Vesta - Ruthenium Make a heterostructure or interface using Vesta If you go through the details of these contents then you can have an idea to make your own multilayer or Interface system which can be comparable with Quantum Espresso. To model any kind of structure, 1st we need the crystallographic information. So we give CIF file as input to the VESTA software. Here are some place...

When I had started learning the basics behind Quantum Espresso, I had come across some very useful resources. Most of them are from Quantum Espresso Tutorial  available on the Quantum espresso website and YouTube. For a beginner, I would like to recommend this amazing seminar by Astrid Marthinsen Here she has beautifully explained all the basics one needs to start working with Quantum Espresso. There are some GUIs available for Quantum Espresso in both windows & Ubuntu operating system  1. BURAI   2. PWgui If you are just starting to learn Quantum Espresso then as per my experience  BURAI   can be a good place to start because here you can get some simpler system with auto-generated input file to start with. So here you will not face any error due to directory or Pseudopotential etc (Unlike PWgui), which may be difficult to deal with initially so you can fully concentrate on learning the input file structure only. I had found t...