Re: [QE-users] bad convergence in field-effect configuration calculations
Dear Thomas, Thanks for the reply and have a nice vacation! Bin From: Dr. Thomas Brumme Sent: Tuesday, September 17, 2019 3:53:17 AM To: Bin Shao Cc: Quantum ESPRESSO users Forum Subject: Re: [QE-users] bad convergence in field-effect configuration calculations Dear Bin, I have no clue if it could be done but it is definitely not implemented. There are problems: Firstly, changing the lattice also changes the doping charge per area and thus the dipole. Yes, this is calculated self-consistently anyways but in the total energy there're parts related to the dipole and the gate interacting with themselves - how to take them properly into account? One would need to go through the equations related to the gate and to stress in order to understand what needs to be done. We just assumed that the influence on the lattice due to the doping is small - which is certainly not true for all materials. If you find a way to implement this, please let me know ;) Thomas Zitat von Bin Shao : > Dear Thomas, > > > > Thank you so much for your reply! I redo the calculation with a > lower doping level and hide the gate in the barrier as you > suggested. The calculation successfully gets converged. However, I > have another question that if we relax the lattice constant of 2D > materials, e.g. graphene, under the field-effect setup, i.e. the > influence of gating on the lattice constant of 2D materials. Is this > meaningful? If yes, can we do this by setting calculation = > ‘relax-vc’ or by calculating the curve of energy vs. lattice constant? > > > > Best, > > Bin > > > > > > > From: Dr. Thomas Brumme > Sent: Monday, September 16, 2019 7:42:59 PM > To: Quantum ESPRESSO users Forum ; > bshao...@outlook.com > Subject: Re: [QE-users] bad convergence in field-effect > configuration calculations > > Dear Bin, > > I can't check your input thoroughly as I'm on vacation, but there are > 2 things I noticed: > > 1. The doping seems quite high - maybe you're close to the van Hove > singularity which could explain problems. Can you try with less doping > and then - if this converges - increase the doping till you get > problems? And plot the total potential - maybe the charge is already > spilling into the vacuum?! This is connected to the second problem: > 2. It can help if you "hide" the gate in the barrier. A typical setup > I used recently: > zgate= 0.589, > emaxpos = 0.59, > eopreg = 0.01, > block= .true., > block_1 = 0.50, > block_2 = 0.60, > block_height = 2.50, > and the system is below 0.5... E.g. for your case, try > zgate = 0.131 > block = .true. > block_1 = 0.13 > block_2 = 0.23 > block_height = 2.5 > edir = 3 > emaxpos = 0.13 > eopreg = 0.01 > The barrier starts with the dipole correction and the gate is right > behind the dipole... Compare with Fig. 2 of the PRB (2014). Also note > that 2.5 Ry for the barrier height is an arbitrarily chosen value - I > noticed other people now also use 2.5 Ry even if 2 Ry or even 1.5 Ry > should be enough. Yet, the higher the doping, the higher the dipole > correction the higher the barrier (if you "hide" everything in the > barrier)... > > Regards & Greeting from the lake Garda in Italy > > Thomas > > Zitat von Bin Shao : > >> Dear all, >> >> I would like to learn how to set up calculations of field-effect >> configuration in quantum espresso. I read the paper "T. Brumme, M. >> Calandra, F. Mauri; PRB 89, 245406 (2014)." and started with >> graphene as an example. The input file is as follows. During the scf >> calculation, there are a lot of warnings like " c_bands: 1 >> eigenvalues not converged". And the calculation could not get >> converged after 800 iterations, could anyone help me with the input >> file? Thanks in advance! >> >> Best regards, >> Bin >> >> >> >> calculation = 'scf' >> etot_conv_thr = 2.00d-05 >> forc_conv_thr = 1.00d-04 >> outdir = './out/' >> prefix = 'aiida' >> pseudo_dir = './pseudo/' >> tprnfor = .true. >> tstress = .true. >> gate = .true. >> dipfield = .true. >> tefield = .true. >> verbosity = 'high' >> / >> >> degauss = 0.02 >> ecutrho = 500 >> ecutwfc = 45 >> ibrav = 0 >> nat = 2 >> ntyp = 1 >> occupations = 'smearing' >> smearing = 'cold' >> tot_charge
Re: [QE-users] bad convergence in field-effect configuration calculations
Dear Bin, I have no clue if it could be done but it is definitely not implemented. There are problems: Firstly, changing the lattice also changes the doping charge per area and thus the dipole. Yes, this is calculated self-consistently anyways but in the total energy there're parts related to the dipole and the gate interacting with themselves - how to take them properly into account? One would need to go through the equations related to the gate and to stress in order to understand what needs to be done. We just assumed that the influence on the lattice due to the doping is small - which is certainly not true for all materials. If you find a way to implement this, please let me know ;) Thomas Zitat von Bin Shao : Dear Thomas, Thank you so much for your reply! I redo the calculation with a lower doping level and hide the gate in the barrier as you suggested. The calculation successfully gets converged. However, I have another question that if we relax the lattice constant of 2D materials, e.g. graphene, under the field-effect setup, i.e. the influence of gating on the lattice constant of 2D materials. Is this meaningful? If yes, can we do this by setting calculation = ‘relax-vc’ or by calculating the curve of energy vs. lattice constant? Best, Bin From: Dr. Thomas Brumme Sent: Monday, September 16, 2019 7:42:59 PM To: Quantum ESPRESSO users Forum ; bshao...@outlook.com Subject: Re: [QE-users] bad convergence in field-effect configuration calculations Dear Bin, I can't check your input thoroughly as I'm on vacation, but there are 2 things I noticed: 1. The doping seems quite high - maybe you're close to the van Hove singularity which could explain problems. Can you try with less doping and then - if this converges - increase the doping till you get problems? And plot the total potential - maybe the charge is already spilling into the vacuum?! This is connected to the second problem: 2. It can help if you "hide" the gate in the barrier. A typical setup I used recently: zgate= 0.589, emaxpos = 0.59, eopreg = 0.01, block= .true., block_1 = 0.50, block_2 = 0.60, block_height = 2.50, and the system is below 0.5... E.g. for your case, try zgate = 0.131 block = .true. block_1 = 0.13 block_2 = 0.23 block_height = 2.5 edir = 3 emaxpos = 0.13 eopreg = 0.01 The barrier starts with the dipole correction and the gate is right behind the dipole... Compare with Fig. 2 of the PRB (2014). Also note that 2.5 Ry for the barrier height is an arbitrarily chosen value - I noticed other people now also use 2.5 Ry even if 2 Ry or even 1.5 Ry should be enough. Yet, the higher the doping, the higher the dipole correction the higher the barrier (if you "hide" everything in the barrier)... Regards & Greeting from the lake Garda in Italy Thomas Zitat von Bin Shao : Dear all, I would like to learn how to set up calculations of field-effect configuration in quantum espresso. I read the paper "T. Brumme, M. Calandra, F. Mauri; PRB 89, 245406 (2014)." and started with graphene as an example. The input file is as follows. During the scf calculation, there are a lot of warnings like " c_bands: 1 eigenvalues not converged". And the calculation could not get converged after 800 iterations, could anyone help me with the input file? Thanks in advance! Best regards, Bin calculation = 'scf' etot_conv_thr = 2.00d-05 forc_conv_thr = 1.00d-04 outdir = './out/' prefix = 'aiida' pseudo_dir = './pseudo/' tprnfor = .true. tstress = .true. gate = .true. dipfield = .true. tefield = .true. verbosity = 'high' / degauss = 0.02 ecutrho = 500 ecutwfc = 45 ibrav = 0 nat = 2 ntyp = 1 occupations = 'smearing' smearing = 'cold' tot_charge = -0.2 zgate = 0.1 block = .true. block_1 = 0.13 block_2 = 0.23 block_height = 2.5 edir = 3 emaxpos = 0.005 eopreg = 0.01 / conv_thr = 1.00d-9 electron_maxstep = 800 mixing_beta = 0.4 mixing_mode = 'local-TF' / ATOMIC_SPECIES C 12.011 C.pbe-n-kjpaw_psl.1.0.0.UPF ATOMIC_POSITIONS crystal C0.00 0.00 0.35 C0.333000 0.667000 0.35 K_POINTS automatic 65 65 1 0 0 0 CELL_PARAMETERS angstrom 2.463800 0.00 0.00 -1.231900 2.1336508000 0.00 0.00 0.00 35.00 == ___ Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users
Re: [QE-users] bad convergence in field-effect configuration calculations
Dear Thomas, Thank you so much for your reply! I redo the calculation with a lower doping level and hide the gate in the barrier as you suggested. The calculation successfully gets converged. However, I have another question that if we relax the lattice constant of 2D materials, e.g. graphene, under the field-effect setup, i.e. the influence of gating on the lattice constant of 2D materials. Is this meaningful? If yes, can we do this by setting calculation = ‘relax-vc’ or by calculating the curve of energy vs. lattice constant? Best, Bin From: Dr. Thomas Brumme Sent: Monday, September 16, 2019 7:42:59 PM To: Quantum ESPRESSO users Forum ; bshao...@outlook.com Subject: Re: [QE-users] bad convergence in field-effect configuration calculations Dear Bin, I can't check your input thoroughly as I'm on vacation, but there are 2 things I noticed: 1. The doping seems quite high - maybe you're close to the van Hove singularity which could explain problems. Can you try with less doping and then - if this converges - increase the doping till you get problems? And plot the total potential - maybe the charge is already spilling into the vacuum?! This is connected to the second problem: 2. It can help if you "hide" the gate in the barrier. A typical setup I used recently: zgate= 0.589, emaxpos = 0.59, eopreg = 0.01, block= .true., block_1 = 0.50, block_2 = 0.60, block_height = 2.50, and the system is below 0.5... E.g. for your case, try zgate = 0.131 block = .true. block_1 = 0.13 block_2 = 0.23 block_height = 2.5 edir = 3 emaxpos = 0.13 eopreg = 0.01 The barrier starts with the dipole correction and the gate is right behind the dipole... Compare with Fig. 2 of the PRB (2014). Also note that 2.5 Ry for the barrier height is an arbitrarily chosen value - I noticed other people now also use 2.5 Ry even if 2 Ry or even 1.5 Ry should be enough. Yet, the higher the doping, the higher the dipole correction the higher the barrier (if you "hide" everything in the barrier)... Regards & Greeting from the lake Garda in Italy Thomas Zitat von Bin Shao : > Dear all, > > I would like to learn how to set up calculations of field-effect > configuration in quantum espresso. I read the paper "T. Brumme, M. > Calandra, F. Mauri; PRB 89, 245406 (2014)." and started with > graphene as an example. The input file is as follows. During the scf > calculation, there are a lot of warnings like " c_bands: 1 > eigenvalues not converged". And the calculation could not get > converged after 800 iterations, could anyone help me with the input > file? Thanks in advance! > > Best regards, > Bin > > > > calculation = 'scf' > etot_conv_thr = 2.00d-05 > forc_conv_thr = 1.00d-04 > outdir = './out/' > prefix = 'aiida' > pseudo_dir = './pseudo/' > tprnfor = .true. > tstress = .true. > gate = .true. > dipfield = .true. > tefield = .true. > verbosity = 'high' > / > > degauss = 0.02 > ecutrho = 500 > ecutwfc = 45 > ibrav = 0 > nat = 2 > ntyp = 1 > occupations = 'smearing' > smearing = 'cold' > tot_charge = -0.2 > zgate = 0.1 > block = .true. > block_1 = 0.13 > block_2 = 0.23 > block_height = 2.5 > edir = 3 > emaxpos = 0.005 > eopreg = 0.01 > / > > conv_thr = 1.00d-9 > electron_maxstep = 800 > mixing_beta = 0.4 > mixing_mode = 'local-TF' > / > ATOMIC_SPECIES > C 12.011 C.pbe-n-kjpaw_psl.1.0.0.UPF > ATOMIC_POSITIONS crystal > C0.00 0.00 0.35 > C0.333000 0.667000 0.35 > K_POINTS automatic > 65 65 1 0 0 0 > CELL_PARAMETERS angstrom > 2.463800 0.00 0.00 > -1.231900 2.1336508000 0.00 > 0.00 0.00 35.00 > == ___ Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users
Re: [QE-users] bad convergence in field-effect configuration calculations
Dear Bin, I can't check your input thoroughly as I'm on vacation, but there are 2 things I noticed: 1. The doping seems quite high - maybe you're close to the van Hove singularity which could explain problems. Can you try with less doping and then - if this converges - increase the doping till you get problems? And plot the total potential - maybe the charge is already spilling into the vacuum?! This is connected to the second problem: 2. It can help if you "hide" the gate in the barrier. A typical setup I used recently: zgate= 0.589, emaxpos = 0.59, eopreg = 0.01, block= .true., block_1 = 0.50, block_2 = 0.60, block_height = 2.50, and the system is below 0.5... E.g. for your case, try zgate = 0.131 block = .true. block_1 = 0.13 block_2 = 0.23 block_height = 2.5 edir = 3 emaxpos = 0.13 eopreg = 0.01 The barrier starts with the dipole correction and the gate is right behind the dipole... Compare with Fig. 2 of the PRB (2014). Also note that 2.5 Ry for the barrier height is an arbitrarily chosen value - I noticed other people now also use 2.5 Ry even if 2 Ry or even 1.5 Ry should be enough. Yet, the higher the doping, the higher the dipole correction the higher the barrier (if you "hide" everything in the barrier)... Regards & Greeting from the lake Garda in Italy Thomas Zitat von Bin Shao : Dear all, I would like to learn how to set up calculations of field-effect configuration in quantum espresso. I read the paper "T. Brumme, M. Calandra, F. Mauri; PRB 89, 245406 (2014)." and started with graphene as an example. The input file is as follows. During the scf calculation, there are a lot of warnings like " c_bands: 1 eigenvalues not converged". And the calculation could not get converged after 800 iterations, could anyone help me with the input file? Thanks in advance! Best regards, Bin calculation = 'scf' etot_conv_thr = 2.00d-05 forc_conv_thr = 1.00d-04 outdir = './out/' prefix = 'aiida' pseudo_dir = './pseudo/' tprnfor = .true. tstress = .true. gate = .true. dipfield = .true. tefield = .true. verbosity = 'high' / degauss = 0.02 ecutrho = 500 ecutwfc = 45 ibrav = 0 nat = 2 ntyp = 1 occupations = 'smearing' smearing = 'cold' tot_charge = -0.2 zgate = 0.1 block = .true. block_1 = 0.13 block_2 = 0.23 block_height = 2.5 edir = 3 emaxpos = 0.005 eopreg = 0.01 / conv_thr = 1.00d-9 electron_maxstep = 800 mixing_beta = 0.4 mixing_mode = 'local-TF' / ATOMIC_SPECIES C 12.011 C.pbe-n-kjpaw_psl.1.0.0.UPF ATOMIC_POSITIONS crystal C0.00 0.00 0.35 C0.333000 0.667000 0.35 K_POINTS automatic 65 65 1 0 0 0 CELL_PARAMETERS angstrom 2.463800 0.00 0.00 -1.231900 2.1336508000 0.00 0.00 0.00 35.00 == ___ Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users
[QE-users] bad convergence in field-effect configuration calculations
Dear all, I would like to learn how to set up calculations of field-effect configuration in quantum espresso. I read the paper "T. Brumme, M. Calandra, F. Mauri; PRB 89, 245406 (2014)." and started with graphene as an example. The input file is as follows. During the scf calculation, there are a lot of warnings like " c_bands: 1 eigenvalues not converged". And the calculation could not get converged after 800 iterations, could anyone help me with the input file? Thanks in advance! Best regards, Bin calculation = 'scf' etot_conv_thr = 2.00d-05 forc_conv_thr = 1.00d-04 outdir = './out/' prefix = 'aiida' pseudo_dir = './pseudo/' tprnfor = .true. tstress = .true. gate = .true. dipfield = .true. tefield = .true. verbosity = 'high' / degauss = 0.02 ecutrho = 500 ecutwfc = 45 ibrav = 0 nat = 2 ntyp = 1 occupations = 'smearing' smearing = 'cold' tot_charge = -0.2 zgate = 0.1 block = .true. block_1 = 0.13 block_2 = 0.23 block_height = 2.5 edir = 3 emaxpos = 0.005 eopreg = 0.01 / conv_thr = 1.00d-9 electron_maxstep = 800 mixing_beta = 0.4 mixing_mode = 'local-TF' / ATOMIC_SPECIES C 12.011 C.pbe-n-kjpaw_psl.1.0.0.UPF ATOMIC_POSITIONS crystal C0.00 0.00 0.35 C0.333000 0.667000 0.35 K_POINTS automatic 65 65 1 0 0 0 CELL_PARAMETERS angstrom 2.463800 0.00 0.00 -1.231900 2.1336508000 0.00 0.00 0.00 35.00 == ___ Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users
