Dear Nick, I read the paper you recommended. The author recommends adding more electrode atoms in the transversal direction in order to reduce the effect of interference due to device images. My question:
1) What is the problem in adding vacuum in the transverse directions? I think it would reduce the effect of interference due to device images. Since already very Thank you. Leone Carmo Garcia 2015-08-19 14:51 GMT-03:00 leoqmc . <[email protected]>: > Dear Nick, > > Thank you. I'll read the paper. > > Leone Carmo Garcia > > 2015-08-19 14:36 GMT-03:00 Nick Papior <[email protected]>: > >> >> >> 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 >> > >
