 Demo - Materials Square

# Materials Square Demo

### DFT Energy

##### 1. Convergence Test: Cutoff Energy
2019-07-24 13:11:40 Convergence test is a way of optimizing a simulation to use limited computational resources efficiently. It is important to find a proper initial input setting for simulation research to decide the accuracy and reliability of the simulation. Read more Calculation Cost
\$ 1.52
##### 2. Convergence Test: K-points
2019-07-24 13:11:40 Convergence test is a way of optimizing a simulation to use limited computational resources efficiently. It is important to find a proper initial input setting for simulation research to decide the accuracy and reliability of the simulation. Read more Calculation Cost
\$ 1.44
##### 3. How to Calculate Cohesive Energy
2019-07-24 13:20:38 The energy for bonding can be calculated using the difference between a bonded structure and a dissociated one. This energy, which is necessary to separate an atom from the solid, is called cohesive energy. Read more Calculation Cost
\$ 0.49
##### 5. Calculation of a Single Atom
2019-07-24 13:41:58 Cohesive energy defined as the difference between the energy per atom in a solid and the energy of a single atom. It can be used to understand the property of crystal such as in finding the correlation effect of an ionic crystal or identifying the stability of the surface. Read more Calculation Cost
\$ 0.82
##### 10-1. Adsorption Energy Obtained through Slab Structure
2019-07-25 01:46:45 Under the adsorption process, the energy change is called adsorption energy. This energy is mainly used when calculating the chemical engineering properties, exploring the adsorption mechanism, or determining the energetic heterogeneity of the surface of a solid. Read more Calculation Cost
\$ 12.54
##### 10-2. Surface Energy Obtained through Slab Structure
2019-07-25 02:01:51 When modeling a slab structure, after the relaxation of the unit cell, use the optimized unit cell to create a slab structure. Then, it can reduce the time for calculating a slab structure. In addition, with the use of the two energies, you can get the surface energy. Read more Calculation Cost
\$ 1.95
##### 11. Stacking Fault Energy
2019-09-09 06:00:11 If some of the crystal is moved, a stacking fault is created. The energy generated by the stacking fault is called stacking fault energy (SFE). The stacking fault energy can be used to determine the thermodynamic stability of a crystal structure or to find out the deformation behavior. Read more Calculation Cost
\$ 114.2
##### 16. Bulk modulus
2019-09-09 06:25:11 For a material is isotropically compressed, at a small volume change, pressure is proportional to the volume strain, and the proportional constant is called the bulk modulus. The bulk modulus could be calculated by applying the data obtained from the several scf calculations. Read more Calculation Cost
\$ 0.81
##### 19. Cohesive Energy with Different Pseudopotentials
2019-08-21 09:36:06 Different pseudopotentials yield different energy values. Therefore, energy values ​​should not be compared directly. But the trend is consistent. So compare the difference in the values. Read more Calculation Cost
\$ 0.46
##### 22. Formation Energy
2019-09-11 04:39:52 Formation Energy is the value to be used as a measure of the amount of energy entering and exiting a chemical reaction, thus providing a basis for determining thermodynamic stability. Read more Calculation Cost
\$ 1.94
##### 25. Van der Waals Correction
2019-10-08 04:38:16 Van der Waals Correction is performed to improve the precision of GGA. Van der Waals Correction, such as DFT+D3, corrects the correlation term of exchange-correlation potential by adding dispersion term. Read more Calculation Cost
\$ 0.36

### Density Of States (DOS)

##### 6. Easy to Get, but Contains a Lot of Information, Density of States(1)
2019-07-24 13:51:44 The density of states (DOS) is the number of different electron states whose occupation is allowed at a specific energy level. DOS is a very important data to describe the electronic structure properties of a macroscopic system quantum-mechanically. Read more Calculation Cost
\$ 11.39
##### 8. Easy to Get, but Contains a Lot of Information, Density of States(3)
2019-07-24 14:43:52 This Example looks at the importance of setting calculation parameters including the number of k-points in DOS calculations. The DOS graph is highly affected by the density of k-points. The DOS graph samples more k-points if denser k-points are set, resulting in a broad graph. Read more Calculation Cost
\$ 0.87
##### 26. Hybrid Functional
2019-10-16 07:57:57 GGA has a fundamental characteristic of underestimating bandgap, Hartree-Fock has an overestimate bandgap. This is due to the exchange potential approximation, so we can correct bandgap and other electronic structures by mixing both functionals. Read more Calculation Cost
\$ 16.91

### Charge Density

##### 17. Charge Density Difference
2019-09-18 09:14:22 With a DFT calculation, you can calculate an electron charge density. With Materials Square, you can conveniently find and visualize the charge density data by carrying out a plane-wave basis DFT calculation of Quantum Espresso. Read more Calculation Cost
\$ 0.25
##### 20. Dipole Correction
2019-08-29 07:20:16 The artificial electric field added automatically to delete a 'potential jump' in the boundary to asymmetry slab structure. So we should do dipole correction by adding a 'sawtooth potential' to the vacuum region to delete the artificial electric field. Read more Calculation Cost
\$ 2.53

### Band Structure

##### 12-1. Band structure (Insulator, Metal)
2019-09-09 06:05:11 An insulator has a sufficient bandgap and the Fermi level is observed within the bandgap. However, of the case of a conductor, the conduction and valence bands are overlapped without any gaps near the Fermi level. Read more Calculation Cost
\$ 16.09
##### 12-2. Band structure (Silicon)
2019-09-09 06:09:11 When you observe the band structure of silicon, the band gaps and the Fermi level existing between them can be seen. However, the band gap moves below or above the Fermi level, thus causing it to be electric property change. Read more Calculation Cost
\$ 7.17
##### 13. Band Structure (k-point, nscf)
2019-09-09 06:19:11 To accurately draw a band structure, you need to set a k-point sampling path by passing the high symmetry point of the Brillouin zone, which depends on the crystal system. Read more Calculation Cost
\$ 3.78
##### 21. Electric Field
2019-09-05 06:05:11 Using the Electric field correction option, we can adjust the bandgap of Graphene bilayer by applying the electric field to the Graphene bilayer. Read more Calculation Cost
\$ 9.74
##### 23. Spin-orbit Coupling
2019-09-18 09:14:22 According to the relativistic theory, the dipole moments of electrons weakly interact with the orbital motions they make. This interaction is called Spin-orbit coupling (SOC). Applying SOC corrections to the simulation yielding the fine-structure of the system. Read more Calculation Cost
\$ 1.21
##### 24. DFT+U
2019-09-27 01:55:42 DFT+U is effective correction method for the correlation energy error in DFT simulation. Read more Calculation Cost
\$ 4.82
##### Electronic Structure for Heterostructure (h-BN/Graphene)
2020-03-27 06:34:23 Heterostructure has unique properties, so many researchers try to find their electronic structure. Calculation Cost
\$ 8.69

### Phonon

##### Silicon Phonon Dispersion
2020-03-24 05:11:58 Phonon dispersion graph is very useful for understanding the electronic structure of the crystal. You can perform the phonon calculation easily in MatSQ. Calculation Cost
\$ 506.8
##### MoS2 Phonon Dispersion (PBE, LDA)
2020-03-24 05:31:58 Phonon dispersion graph is very useful for understanding the electronic structure of the crystal. You can use any functional you want. Calculation Cost
\$ 511.6