Topics

1

General Questions and Answers / Gate voltage calculations in ATK

« on: April 22, 2016, 14:23 »

Dear QuantumWise Staff,

Can you please provide more details about how three terminal calculations are done in ATK ?
Is this published or documented somewhere ?

Thanks
Kanna

2

General Questions and Answers / noise calculation

« on: March 3, 2016, 20:11 »

Hi,
Is there a way to calculate noise in a device with ATK ?

Regards
Kanna

3

General Questions and Answers / understanding memory consumption

« on: January 20, 2016, 10:15 »

Hi,

In the log

| Size of dense matrices = 10516 x 10516 [1687 MB per matrix]                  |

|                                                                              |
| Storage of orbitals in real space is disabled.                               |
| Enabling storage requires an additional   607 MB.                            |
|                                                                              |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
|                                                                              |
| Real space grid sampling is (61, 111, 773) in a, b, and c directions.        |
|                                                                              |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
|                                                                              |
| Storage of atomic core grids requires    39 MB per grid                      |
|                                                                              |
+------------------------------------------------------------------------------+

• I think the dense matrices are formed from the sparse matrices in the calculation , but how many such dense matrices are used ? In my simulation each mpi thread takes 10.9 GB of memory.
• How is the real space sampling controlled ? I am guessing it is related to the resolution of k points we give in the calculation , am I correct to assume this ?
• How many atomic core grids are present ? Is this the number of atoms in the structure * 39MB in this case ?Does this depend on the basis set (SZP/DZP) and exchange correlation alone ?[\li]
  

Thanks
kanna

4

General Questions and Answers / calculation of gate oxide capacitance

« on: January 19, 2016, 15:46 »

Can we calculate the gate oxide capacitance of a mosfet with the tutorial given in
http://quantumwise.com/publications/tutorials/item/511-calculation-of-atomic-scale-capacitance ?

5

General Questions and Answers / cluster configuration

« on: January 14, 2016, 09:33 »

We are thinking of buying a new cluster and extra licenses. Is there something special which we need to look for ?

Should we invest more on
1. CPU frequency
2. memory per node
3. frequency of operation of the memory
4. SSD drive or SATA drive
5. any cards for mpi communication?
6. Choice of operating system

Please let us know if there is some tradeoff within the features which we can follow to optimize our cost.

Typically we run optimization and transport with electron-phonon model for 1000 TMD's.