2015-08-19 17:14 GMT+00:00 leoqmc . <[email protected]>: > Dear Nick, > > I prepared my inputs following your tips and test inputs. I'm waiting for the > calculations to complete. But one question remains. > > 1) I want to get the transport properties in a single molecule and not > added vacuum in either direction (as the tests that you recommended). The > results will not be influenced by the "images" of my device? > Sure they will. :)
> > > 2) I have seen examples that use large vacuum in the x and y directions. When > this is recommended? > This is a drawback of the supercell approach, however, please look through litterature for this. This article touches upon that: 10.1103/PhysRevB.72.033401, as well as how to circumvent 1). > > > From already thank you very much. > > Leone Carmo Garcia > > 2015-08-19 8:47 GMT-03:00 leoqmc . <[email protected]>: > >> Dear Nick, >> >> I am very grateful for your help. I will follow the tips. >> >> Leone Carmo Garcia >> >> 2015-08-18 16:42 GMT-03:00 Nick Papior <[email protected]>: >> >>> >>> >>> 2015-08-18 19:27 GMT+00:00 leoqmc . <[email protected]>: >>> >>>> Dear Nick and transiesta users, >>>> >>>> I am interested in transport calculations in single-molecule two-probe >>>> systems[Au(111)-Molecule-Au(111)]. I searched in the list for the following >>>> questions, but I think that these questions were not explicitly solved for >>>> a beginner. Please help me. >>>> >>>> 1) Charge: The Molecule is charged(charge +2). Not make sense uses the >>>> option (NetCharge 2.0) in the transiesta calculation, since that the charge >>>> will be screened. I'm right? >>>> >>> No that will most likely not work, currently this is not an easy task. >>> >>>> >>>> 2) Setup for the electrodes: >>>> a) The third lattice's vector (z-direction) should have length >>>> minimal possible, namely it should be enough for the atoms+basis functions. >>>> I'm right? >>>> >>> In your case, make the z-direction periodic. >>> >>>> b) The lattice's vectors in x,y direction should include large >>>> vacuum (~20 Angstroms). I'm right? >>>> >>> No, not necessarily, here you can also impose periodicity. Please look >>> at the examples in the test directory, an example of gold, gold-chain, gold >>> is shown. That could be the basis for your further geometry creation. See >>> example ts_au_100, both the repetition and non-repeated structure. >>> >>>> c) Usually you use how many units ("N") of the electrodes (N * ABC)? >>>> >>> In your 111 direction I would think a single ABC stacking should be >>> enough. This depends on your basis range, you need to check this your-self. >>> >>>> >>>> 3) Setup for complete device (Electrodes + Molecule): >>>> >>>> a) My electrodes are equal. In this case it is mandatory to include >>>> vacuum in the z direction, such that the device is not affected by their >>>> image in the calculation of siesta prior to the calculation of transiesta? >>>> >>> Please re-read 2a. If electrodes are the same, having a periodic setup >>> is far better than the alternative. Again refer to the example as suggested >>> in 2b. >>> >>>> >>>> Thanks in advance. >>>> >>>> Leone Carmo Garcia >>>> >>> >>> >>> >>> -- >>> Kind regards Nick >>> >> >> > -- Kind regards Nick
