From giovanni.pizzi at epfl.ch Thu Jul 6 15:49:54 2017 From: giovanni.pizzi at epfl.ch (Giovanni Pizzi) Date: Thu, 6 Jul 2017 13:49:54 +0000 Subject: [Wannier] confusion on conductivity tensor calculation In-Reply-To: References: Message-ID: <7693485B-BA60-49C8-854D-0A0EA2D7B1E7@epfl.ch> Hi, When I was speaking of convergence issues, I was not thinking to the preliminary DFT computation, but mainly to the convergence with the dense grid in BoltzWann - the calculation includes a derivative of a Fermi-Dirac distribution, that is a Dirac-delta in the zero-temperature limit. Smearing (of the TDF, in BoltzWann) can help but I think will give an incorrect result in practice. Also, the Seebeck coefficient calculation requires to invert a matrix, and at low temperature with the chemical potential in the electronic gap, one risks to ask the code to invert a matrix with basically zero eigenvalues, which is also a problem. Giovanni -- Giovanni Pizzi Theory and Simulation of Materials and MARVEL, EPFL http://people.epfl.ch/giovanni.pizzi http://nccr-marvel.ch/en/people/profile/giovanni-pizzi On 25 Jun 2017, at 05:23, Jun Liu > wrote: Dear Prof. Giovanni, Thank you very much for your help. I do need to see how conductivity changes across the three cases I mentioned under T=2K. But I should be satisfied with the trend of change if the results look reasonable at higher T. I have submitted jobs for T=50K and see how they will work out (still not finished yet). Could you please elaborate on what you mean by numerical and convergence issues? I think I should have at least reached K-points and ENCUT convergence. Thanks, Sincerely, Jun On Thu, Jun 15, 2017 at 12:24 PM, Giovanni Pizzi > wrote: Dear Jun, You are working in the range of temperatures 2-10 K. Is this expected? Such low temperatures are very hard to work with in the code, because of numerical and convergence issues. If you work at higher temperature, is the result better? Also, remember that by changing the strain you will change the energy position of the bands (as basically all materials have non-zero deformation potentials) and therefore you cannot really compare values at the same exact chemical potential mu. E.g. it is possible that when you get close to zero, it is because at that strain there?s no band close to the chemical potential (and since you are at low T, you need bands really close). Changing strain, bands enter in the region. I suggest that you start by T>50K (and without boltz_tdf_smr_fixed_en_width) and you compare the whole plots in a chemical potential range, and once you understand the behaviour you go down in temperature, potentially putting back some smearing in the TDF, to check also if you are converged enough. Note however that the TDF smearing while probably needed at low T, might introduce some errors in the final results. Hope this helps, Giovanni -- Giovanni Pizzi Theory and Simulation of Materials and MARVEL, EPFL http://people.epfl.ch/giovanni.pizzi http://nccr-marvel.ch/en/people/profile/giovanni-pizzi On 31 May 2017, at 18:42, Jun Liu > wrote: Dear wannier users, I would like to ask whether the following input for conductivity tensor calculation looks ok. num_bands = 128 ! set to NBANDS by VASP num_wann = 88 begin projections Mo:d ! 20 Te:p ! 24 end projections ###########BoltzWann ############ boltzwann = true kmesh = 400 400 400 boltz_relax_time = 0.001 boltz_mu_min = 7.95123782 #ef-def boltz_mu_max = 8.35123782 boltz_mu_step = 0.04 boltz_temp_min = 2 boltz_temp_max = 10 boltz_temp_step = 2 boltz_tdf_energy_step=0.01 boltz_tdf_smr_fixed_en_width = 0.01 boltz_tdf_smr_type = gauss boltz_calc_also_dos = true boltz_dos_energy_min = 5.0 boltz_dos_energy_max = 15.0 boltz_dos_energy_step = 0.01 ################################# write_hr = .true. # Bandstructure restart = plot bands_plot = true begin kpoint_path .... end kpoint_path bands_num_points 100 # bands_plot_format gnuplot spinors = .true. begin unit_cell_cart 3.4716802 0.0000000 0.0000000 /*this and the next line changes*/ 0.0000000 6.3666750 0.0000000 /*accordingly for different cases*/ 0.0000000 0.0000000 13.8452386 end unit_cell_cart begin atoms_cart ... end atoms_cart mp_grid = 12 6 3 /*this line differs from each case*/ begin kpoints ... end kpoints This input returns reasonable result (in that the conductivity tensor is nearly diagonal for orthorhombic structure). But if I compare results across different cases, they differ too much under as small as 0.5% lattice constant change. More details are given below. I tried to calculate the conductivity tensor with postw90.x with version 2.1. I tried it on three cases related with slight elongation along a or b directions defining an orthorhombic structure on the original lattice. The resulting conductivity tensor differs by nearly 100% for a 0.5% lattice constant change, which cannot be right. To give you some numbers, the following shows different sigma_x,x scanned under different chemical potentials for different lattice structures, (other components of sigma are suppressed for brevity but the whole sigma matrix does show a diagonal feature expected for an orthorhombic structure.) For the base structure (a,b,c) mu T sigma_x,x 7.963542580 2.000000000 0.4228380355E-05 7.963542580 4.000000000 0.6146815602E-01 7.963542580 6.000000000 1.261398051 7.963542580 8.000000000 5.250207712 7.963542580 10.00000000 11.71261179 For the elongated structure along a by 0.5% mu T sigma_x,x 7.962242580 2.000000000 0.5201871790E-03 7.962242580 4.000000000 0.6688530829 7.962242580 6.000000000 6.051666588 7.962242580 8.000000000 16.35207686 7.962242580 10.00000000 27.52636769 For the elongated structure along b by 0.5% mu T sigma_x,x 7.951237820 2.000000000 332.9039665 7.951237820 4.000000000 363.9745377 7.951237820 6.000000000 287.1196636 7.951237820 8.000000000 228.9187157 7.951237820 10.00000000 188.4869745 Any idea on how to check the calculation? Thanks all very much for your insightful help! Sincerely, Jun _______________________________________________ Wannier mailing list Wannier at quantum-espresso.org http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier _______________________________________________ Wannier mailing list Wannier at quantum-espresso.org http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier -------------- next part -------------- An HTML attachment was scrubbed... URL: From blueway39 at korea.ac.kr Tue Jul 11 04:07:22 2017 From: blueway39 at korea.ac.kr (=?UTF-8?B?WW91bmctSm9vbiBTb25n?=) Date: Tue, 11 Jul 2017 11:07:22 +0900 (KST) Subject: [Wannier] =?utf-8?q?unit_cell_and_formula_unit?= Message-ID: <596435473fe2_@_imoxion.com> Dear users and developers? Hello. ? I?d like to ask a question related to the unit cell used in the Wannier90 code. Recently, I study on rhombohedral structure system. This structure can transform to hexagonal one. In my case, the difference of formula unit between rhombohedral cell and hexagonal cell is three times. After DFT calculation using WIEN2K code, I got MLWFs of both cases separately. Then I calculated the anomalous Hall conductivity with ?postw90.x?. Here is my question. Why are these values of the anomalous Hall conductivity similar in both cases of rhombohedral cell and hexagonal cell even their formula units are not same. I think these values should be different by three times. ? Any comment is very helpful for me. ? Thank you in advance. -------------- next part -------------- An HTML attachment was scrubbed... URL: From jonathan.yates at materials.ox.ac.uk Tue Jul 11 16:38:11 2017 From: jonathan.yates at materials.ox.ac.uk (Jonathan Yates) Date: Tue, 11 Jul 2017 15:38:11 +0100 Subject: [Wannier] unit cell and formula unit In-Reply-To: <596435473fe2_@_imoxion.com> References: <596435473fe2_@_imoxion.com> Message-ID: Dear Young-Joon, The AHC is reported in units of (Ohm cm)^-1 - it is a bulk property. So it should not matter if you study one unit cell, or 10, or 1000 unit cells, you should get the same answer. The fact that you get the same answer for the rhombohedral and hexagonal representations of the same crystal is a actually a nice validation of the method? By contrast, properties such as the orbital magnetisation are extensive (e.g. postw90 reports a magnetisation per unit cell) Jonathan > On 11 Jul 2017, at 03:07, Young-Joon Song wrote: > > Dear users and developers > > > > Hello. > > > > I?d like to ask a question related to the unit cell used in the Wannier90 code. Recently, I study on rhombohedral structure system. > > This structure can transform to hexagonal one. In my case, the difference of formula unit between rhombohedral cell and hexagonal cell is three times. > > After DFT calculation using WIEN2K code, I got MLWFs of both cases separately. Then I calculated the anomalous Hall conductivity with ?postw90.x?. > > Here is my question. Why are these values of the anomalous Hall conductivity similar in both cases of rhombohedral cell and hexagonal cell even their formula units are not same. > > I think these values should be different by three times. > > > > Any comment is very helpful for me. > > > > Thank you in advance. > > > Young-Joon Song > > _______________________________________________ > Wannier mailing list > Wannier at quantum-espresso.org > http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier -------------- next part -------------- An HTML attachment was scrubbed... URL: From jiachenchem at gmail.com Sun Jul 16 01:39:11 2017 From: jiachenchem at gmail.com (Jia Chen) Date: Sat, 15 Jul 2017 19:39:11 -0400 Subject: [Wannier] Is it possible to have Fermi velocity from wannier of boltzwann calculation? Message-ID: Dear all, I have been trying to calculate Fermi velocity. The transport distribution function at Fermi level looks close to the square of that, but there is quantity with dimension of energy^(-1) from \delta(E-E_{n,k}) I can't figure out. I wonder if someone here has worked on this issue before. Appreciate it. Cheers Jia -------------- next part -------------- An HTML attachment was scrubbed... URL: From greschd at phys.ethz.ch Sun Jul 23 22:59:11 2017 From: greschd at phys.ethz.ch (Dominik Gresch) Date: Sun, 23 Jul 2017 22:59:11 +0200 Subject: [Wannier] projections vs. spinor_projections blocks Message-ID: <2db9988e-5527-8073-a5c7-1580db5b4712@phys.ethz.ch> Dear Wannier90 community, I have a question regarding the use of the "projections" and "spinor_projections" blocks: In chapter 3.2 of the user guide, the "projections" block is used to define spinor projections. However, in 5.1.6, the same input is described as the "spinor_projections" block. A quick search in the code revealed that in parameters.F90, only "projections" is used, but not "spinor_projections". On the other hand, kmesh.F90 writes the "spinor_projections" block, and the it seems that pw2wannier90 reads it. So my question is this: What is the exact difference in using "spinor_projections" or "projections"? Can they be used interchangeably, or should it always be "spinor_projections" when the spin part is set? If the two are equivalent, what is the preferred method? Best regards, Dominik Gresch From i.aguilera at fz-juelich.de Tue Jul 25 16:14:09 2017 From: i.aguilera at fz-juelich.de (Aguilera, Irene) Date: Tue, 25 Jul 2017 14:14:09 +0000 Subject: [Wannier] Kramers degeneracy broken by Wannier interpolation In-Reply-To: <6C025142-440B-4529-89E0-3967E78709C1@fz-juelich.de> References: <6C025142-440B-4529-89E0-3967E78709C1@fz-juelich.de> Message-ID: <25510DD7E9E2BA4EA7151BB3E152A3866AEDB933@MBX2010-E01.ad.fz-juelich.de> Dear all, somebody suggested me to use "use_ws_distance = .true.". This seems to have solved the problem with the broken Kramers degeneracy. Thanks to everybody who gave me suggestions. Best, Irene ________________________________ From: Aguilera, Irene Sent: Wednesday, June 21, 2017 2:32 PM To: wannier at quantum-espresso.org Subject: Kramers degeneracy broken by Wannier interpolation Dear all, this is a general question about the Wannier interpolation technique. I'm using wannier90 to perform a Wannier interpolation for a system with inversion symmetry (IS), time-reversal (TRS) symmetry, and spin-orbit coupling. Therefore, all states must be doubly degenerate (Kramers pairs). The interpolated band structure is in excellent agreement with the explicitly calculated one (DFT or GW). The construction of the Wannier functions seems correct and the bands at the k points which are present in the explicit DFT or GW calculation are indeed doubly degenerate. But this is not the case for the arbitrary k points (q) at which the bands are interpolated. For those q points there is a small splitting between the Kramers partners. I do understand the following: In order for the Kramers degneracy to be preserved, the Hamiltonian has to be invariant with respect to a certain symmetry operation (IS+TRS in this case): H(k) = S^T(k)*H(k)*S(k) where S(k) is the corresponding transformation matrix. This transformation matrix is k-dependent. For the explicit k points, the above condition is fulfilled. For an interpolated q point, we would have to demand H(q) = S^T(q)*H(q)*S(q) (*) However, in the Wannier interpolation, H(q) is a linear combination of the H(k): H(q) = SUM(k) c(q,k) H(k) with some coefficients c(q,k). This probably leads to the fact that, because of the k dependence of S(k), the requirement (*) is not fulfilled (in general), and therefore the degeneracy is lifted. So, I think I understand why this happens and I understand how to improve it and make the splitting negligible (increasing the k points in the DFT calculation does it). But I cannot find a solution to obtain real degeneracies and I could not find discussions about this issue in the literature or in the forum. Are there approaches to solve this problem? How can one symmetrize H(q)? Can one impose some conditions on H(R) (the Hamiltonian in real space) such that H(q) presents the correct symmetries? Thank you very much. Best regards, Irene ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------ Forschungszentrum Juelich GmbH 52425 Juelich Sitz der Gesellschaft: Juelich Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Dr. Karl Eugen Huthmacher Geschaeftsfuehrung: Prof. Dr.-Ing. Wolfgang Marquardt (Vorsitzender), Karsten Beneke (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt, Prof. Dr. Sebastian M. Schmidt ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------ -------------- next part -------------- An HTML attachment was scrubbed... URL: From esandhar at email.uark.edu Mon Jul 31 18:30:03 2017 From: esandhar at email.uark.edu (Eesha Andharia) Date: Mon, 31 Jul 2017 11:30:03 -0500 Subject: [Wannier] Reg. using kmesh.pl utility and K-point error Message-ID: Hi, Is there a specific input file for wannier90 utility kmesh.pl to generate the k-points? How to use the executable? Also, what does the following error in the K-Point path indicate: param_get_keyword_kpath: Problem reading kpath g 0.000 0.000 0.000 Regards, Eesha -------------- next part -------------- An HTML attachment was scrubbed... URL: From a.mostofi at imperial.ac.uk Mon Jul 31 18:35:48 2017 From: a.mostofi at imperial.ac.uk (Mostofi, Arash) Date: Mon, 31 Jul 2017 16:35:48 +0000 Subject: [Wannier] projections vs. spinor_projections blocks In-Reply-To: <2db9988e-5527-8073-a5c7-1580db5b4712@phys.ethz.ch> References: <2db9988e-5527-8073-a5c7-1580db5b4712@phys.ethz.ch> Message-ID: <276D4DF3-6C5F-4B6A-B5F2-7DB8D57634E5@ic.ac.uk> Dear Dominik, If spinors=true in the .win file, then a ?spinor_projections" block is written to the nnkp file; otherwise it?s a ?projections? block. In both cases, the projections are defined in the .win file within the ?projections? block (see Ch 3 of user guide). This was done to preserve backward compatability when spinor projections were added. Hope that helps! Arash ? Arash Mostofi ? www.mostofigroup.org Director, Thomas Young Centre @Imperial Imperial College London On 23 Jul 2017, at 21:59, Dominik Gresch > wrote: Dear Wannier90 community, I have a question regarding the use of the "projections" and "spinor_projections" blocks: In chapter 3.2 of the user guide, the "projections" block is used to define spinor projections. However, in 5.1.6, the same input is described as the "spinor_projections" block. A quick search in the code revealed that in parameters.F90, only "projections" is used, but not "spinor_projections". On the other hand, kmesh.F90 writes the "spinor_projections" block, and the it seems that pw2wannier90 reads it. So my question is this: What is the exact difference in using "spinor_projections" or "projections"? Can they be used interchangeably, or should it always be "spinor_projections" when the spin part is set? If the two are equivalent, what is the preferred method? Best regards, Dominik Gresch _______________________________________________ Wannier mailing list Wannier at quantum-espresso.org http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier -------------- next part -------------- An HTML attachment was scrubbed... URL: From a.mostofi at imperial.ac.uk Mon Jul 31 19:03:02 2017 From: a.mostofi at imperial.ac.uk (Mostofi, Arash) Date: Mon, 31 Jul 2017 17:03:02 +0000 Subject: [Wannier] Error during quantum conductance calculation In-Reply-To: <20170630104659.Horde.P5iXOK0SJ3JTH2z8Psq5z6O@webmail.auth.gr> References: <20170630104659.Horde.P5iXOK0SJ3JTH2z8Psq5z6O@webmail.auth.gr> Message-ID: <5059EF4A-EA09-4E31-AA0B-E0058BA8C7CD@ic.ac.uk> Hello, One of the conventions for the use of this mailing list is to sign with your name and affiliation in all posts, and we would all be very grateful if you would please adhere to this convention. I think the error you report below means that your one_dim_axis (the Cartesian y direction in your example) is not aligned with one of the supercell vectors (the vectors in the Unit_Cell_Cart block of the input file). Hope this helps. Arash ? Arash Mostofi ? www.mostofigroup.org Director, Thomas Young Centre @Imperial Imperial College London On 30 Jun 2017, at 08:46, elchatz at auth.gr wrote: Hello, I am getting the following error during the quantum conductance calculation: -------------------------------------------------------------------------------- 0 : 1-D LATTICE VECTOR NOT DEFINED Exiting....... Error: 1-d lattice vector not defined in tran_reduce_hr --------------------------------------------------------------------------------- The band calculation for the same system gave accurate results. My .win file is the following: --------------------------------------------------------------------------------- num_bands = 1100 num_wann = 550 conv_tol = 1.0d-9 conv_window = 20 !dis_win_max = 2.0 !dis_froz_max = 0.0 dis_conv_tol = 1.0d-9 dis_conv_window = 20 num_print_cycles = 40 # Transport transport = .true. transport_mode = lcr tran_read_ht = .false. one_dim_axis = y fermi_energy = -1.9803318976567956 tran_win_min = -4 tran_win_max = 4 tran_num_cell_ll = 2 tran_num_ll = 100 tran_energy_step = 0.01 translation_centre_frac = 0.0 0.0 0.0 !dist_cutoff = 13.35 dist_cutoff_mode = one_dim mp_grid : 1 1 1 gamma_only = .true. begin kpoints 0.0000 0.0000 0.0000 end kpoints Begin Unit_Cell_Cart Angstrom [...] End Unit_Cell_Cart begin atoms_cart Angstrom [..] End atoms_cart begin projections random end projections ----------------------------------------------------------------------- Any advice? _______________________________________________ Wannier mailing list Wannier at quantum-espresso.org http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier -------------- next part -------------- An HTML attachment was scrubbed... URL: From greschd at phys.ethz.ch Mon Jul 31 22:46:10 2017 From: greschd at phys.ethz.ch (Dominik Gresch) Date: Mon, 31 Jul 2017 22:46:10 +0200 Subject: [Wannier] projections vs. spinor_projections blocks In-Reply-To: <276D4DF3-6C5F-4B6A-B5F2-7DB8D57634E5@ic.ac.uk> References: <2db9988e-5527-8073-a5c7-1580db5b4712@phys.ethz.ch> <276D4DF3-6C5F-4B6A-B5F2-7DB8D57634E5@ic.ac.uk> Message-ID: <8f554968-e704-5e64-9221-7a6e08f6f789@phys.ethz.ch> Dear Arash, Thanks, I missed the point that "spinor_projections" was only in the nnkpts file. Now it's all clear. Best, Dominik On 31.07.2017 18:35, Mostofi, Arash wrote: > Dear Dominik, > > If spinors=true in the .win file, then a ?spinor_projections" block is > written to the nnkp file; otherwise it?s a ?projections? block. In > both cases, the projections are defined in the .win file within the > ?projections? block (see Ch 3 of user guide). This was done to > preserve backward compatability when spinor projections were added. > > Hope that helps! > > Arash > > ? > Arash Mostofi ? www.mostofigroup.org > Director, Thomas Young Centre @Imperial > Imperial College London > > > >> On 23 Jul 2017, at 21:59, Dominik Gresch > > wrote: >> >> Dear Wannier90 community, >> >> I have a question regarding the use of the "projections" and >> "spinor_projections" blocks: >> >> In chapter 3.2 of the user guide, the "projections" block is used to >> define spinor projections. However, in 5.1.6, the same input is >> described as the "spinor_projections" block. >> >> A quick search in the code revealed that in parameters.F90, only >> "projections" is used, but not "spinor_projections". On the other >> hand, kmesh.F90 writes the "spinor_projections" block, and the it >> seems that pw2wannier90 reads it. >> >> So my question is this: What is the exact difference in using >> "spinor_projections" or "projections"? Can they be used >> interchangeably, or should it always be "spinor_projections" when the >> spin part is set? If the two are equivalent, what is the preferred >> method? >> >> Best regards, >> >> Dominik Gresch >> >> _______________________________________________ >> Wannier mailing list >> Wannier at quantum-espresso.org >> http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier > > > > _______________________________________________ > Wannier mailing list > Wannier at quantum-espresso.org > http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier -------------- next part -------------- An HTML attachment was scrubbed... URL: