GW on h-BN (standalone) - Revision history

Giacomo.sesti: /* Converging Screening Parameters */

2025-05-18T13:49:50Z

Converging Screening Parameters

← Older revision		Revision as of 13:49, 18 May 2025
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	* Even if not totally converged we can consider that the upper limit of <code>[[Variables#BndsRnXp\|BndsRnXp]]</code>=30, and <code>[[Variables#NGsBlkXp\|NGsBlkXp]]</code>=3Ry are reasonable parameters.		* Even if not totally converged we can consider that the upper limit of <code>[[Variables#BndsRnXp\|BndsRnXp]]</code>=30, and <code>[[Variables#NGsBlkXp\|NGsBlkXp]]</code>=3Ry are reasonable parameters.

	Finally notice that in the ~~last versions~~ of Yambo (from 4.5 etc.) there is a terminator for the dielectric constant that accelerates convergence on the number of bands,		Finally notice that in the current version of Yambo (from 4.5 etc.) there is a terminator for the dielectric constant that accelerates convergence on the number of bands,
	you can active it setting <code>XTermKind= "BG"</code>. You can compare the converge of the dielectric constant with and without terminator,		you can active it setting <code>XTermKind= "BG"</code>. You can compare the converge of the dielectric constant with and without terminator,
	similar to what happens for the self-energy, see next section.		similar to what happens for the self-energy, see next section.

Giacomo.sesti: /* Converging Screening Parameters */

2025-05-18T13:45:48Z

Converging Screening Parameters

← Older revision		Revision as of 13:45, 18 May 2025
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	Finally notice that in the last versions of Yambo (from 4.5 etc.) there is a terminator for the dielectric constant that accelerates convergence on the number of bands,		Finally notice that in the last versions of Yambo (from 4.5 etc.) there is a terminator for the dielectric constant that accelerates convergence on the number of bands,
	you can active it ~~with the <code>-V resp</code> verbosity and~~ setting <code>XTermKind= "BG"</code>. You can compare the converge of the dielectric constant with and without terminator,		you can active it setting <code>XTermKind= "BG"</code>. You can compare the converge of the dielectric constant with and without terminator,
	similar to what happens for the self-energy, see next section.		similar to what happens for the self-energy, see next section.

Giacomo.sesti: /* Understanding the output */

2025-05-18T13:36:15Z

Understanding the output

← Older revision		Revision as of 13:36, 18 May 2025
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	# K-point Band Eo E-Eo Sc\|Eo		# K-point Band Eo E-Eo Sc\|Eo
	#		#
	7 8 -0.411876 -0.567723 2.322443		7 8 -0.411876 -0.567723 2.322443
	7 9 3.877976 2.413773 -2.232241		7 9 3.877976 2.413773 -2.232241

	In the header you can see the details of the calculations, for instance it reports that <code>[[Variables#NGsBlkXp\|NGsBlkXp]]</code>=1 Ry corresponds to 5 Gvectors:		In the header you can see the details of the calculations, for instance it reports that <code>[[Variables#NGsBlkXp\|NGsBlkXp]]</code>=1 Ry corresponds to 5 Gvectors:

Giacomo.sesti: /* Secant Solver */

2025-05-18T13:35:19Z

Secant Solver

← Older revision		Revision as of 13:35, 18 May 2025
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	# K-point Band Eo E-Eo Sc\|Eo		# K-point Band Eo E-Eo Sc\|Eo
	#		#
	7 8 -0.41188 -0.08708 2.91254		7 8 -0.41188 -0.08708 2.91254
	7 9 3.877976 1.421968 -3.417357		7 9 3.877976 1.421968 -3.417357

	''o-ff100.qp_01'' '''Secant Solver:'''		''o-ff100.qp_01'' '''Secant Solver:'''
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	# K-point Band Eo E-Eo Sc\|Eo		# K-point Band Eo E-Eo Sc\|Eo
	#		#
	7 8 -0.41188 -0.08715 2.93518		7 8 -0.41188 -0.08715 2.93518
	7 9 3.877976 1.401408 -3.731649		7 9 3.877976 1.401408 -3.731649

Giacomo.sesti: /* Step 3: Interpolating Band Structures */

2025-05-18T13:34:07Z

Step 3: Interpolating Band Structures

← Older revision		Revision as of 13:34, 18 May 2025
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	# K-point Band Eo E-Eo Sc\|Eo		# K-point Band Eo E-Eo Sc\|Eo
	#		#
	1~~.000000~~ 6~~.000000~~ -1.299712 -0.219100 3.788044		1 6 -1.299712 -0.219100 3.788044
	1~~.000000~~ 7~~.000000~~ -1.296430 -0.241496 3.788092		1 7 -1.296430 -0.241496 3.788092
	1~~.000000~~ 8~~.000000~~ -1.296420 -0.243115 3.785947		1 8 -1.296420 -0.243115 3.785947
	1~~.000000~~ 9~~.000000~~ 4.832399 0.952386 -3.679259		1 9 4.832399 0.952386 -3.679259
	1~~.00000~~ 10~~.00000~~ 10.76416 2.09915 -4.38743		1 10 10.76416 2.09915 -4.38743
	1~~.00000~~ 11~~.00000~~ 11.36167 2.48053 -3.91021		1 11 11.36167 2.48053 -3.91021
	....		....
	By plotting some of the 'o-all_Bz.qp" columns it is possible to discuss some physical properties of the hBN QPs. Using columns 3 and (3+4), ie plotting the GW energies with respect to the LDA energies we can deduce the band gap renormalization and the stretching of the conduction/valence bands:		By plotting some of the 'o-all_Bz.qp" columns it is possible to discuss some physical properties of the hBN QPs. Using columns 3 and (3+4), ie plotting the GW energies with respect to the LDA energies we can deduce the band gap renormalization and the stretching of the conduction/valence bands:

Giacomo.sesti: /* Accelerating the sum over states convergence in the correlation self-energy */

2025-05-18T13:31:18Z

Accelerating the sum over states convergence in the correlation self-energy

← Older revision		Revision as of 13:31, 18 May 2025
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	[[Variables#GTermKind\|GTermKind]]= "BG"		[[Variables#GTermKind\|GTermKind]]= "BG"

	in the file ''gw_ppa_Gbnd10.in'' ~~or simply you can modify by hand~~ this ~~line~~ in all the other ''gw_ppa_GbndX.in'' input files.		for example in the file ''gw_ppa_Gbnd10.in''. Now, repeat this operation also in all the other ''gw_ppa_GbndX.in'' input files.
	~~Now we~~ can ~~repeat~~ the same calculations		We can now perform once again the same calculations with the terminator activated

	$ yambo -F gw_ppa_Gbnd10.in -J Gbnd10_term		$ yambo -F gw_ppa_Gbnd10.in -J Gbnd10_term

Giacomo.sesti at 13:29, 18 May 2025

2025-05-18T13:29:32Z

← Older revision		Revision as of 13:29, 18 May 2025
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	In general the convergence with respect the sum over states can be very cumbersome. Here we show how it can be mitigated by using		In general the convergence with respect the sum over states can be very cumbersome. Here we show how it can be mitigated by using
	a technique developed by F. Bruneval and X. Gonze <ref name="BG"> F. Bruneval and X. Gonze, Physical Review B 78, 085125 (2008 )</ref>. The basic idea relies in replacing the eigenenergies of the states that are not treated explicitly by a common energy, and take into account all the states, which are not explicitly included in the calculation through the closure relation.		a technique developed by F. Bruneval and X. Gonze <ref name="BG"> F. Bruneval and X. Gonze, Physical Review B 78, 085125 (2008 )</ref>. The basic idea relies in replacing the eigenenergies of the states that are not treated explicitly by a common energy, and take into account all the states, which are not explicitly included in the calculation through the closure relation.
	To apply this technique in Yambo we need to activate the optional terminator variable [[Variables#GTermKind\|GTermKind]]. ~~We can activate it by adding the quasiparticle verbosity to the command line when generating the input file:~~		To apply this technique in Yambo we need to activate the optional terminator variable [[Variables#GTermKind\|GTermKind]]. You can edit the input file by setting:

	~~$ yambo -p p -g n -F gw_ppa_Gbnd10.in -V qp~~

	~~and you~~ can edit the input file by setting:

	[[Variables#GTermKind\|GTermKind]]= "BG"		[[Variables#GTermKind\|GTermKind]]= "BG"

	or simply you can ~~add~~ by hand this line in all the other ''gw_ppa_GbndX.in'' input files.		in the file ''gw_ppa_Gbnd10.in'' or simply you can modify by hand this line in all the other ''gw_ppa_GbndX.in'' input files.
	Now we can repeat the same calculations		Now we can repeat the same calculations

Giacomo.sesti at 13:23, 18 May 2025

2025-05-18T13:23:08Z

← Older revision		Revision as of 13:23, 18 May 2025
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	Once the jobs are terminated we can collect the quasiparticle energies for fixed <code>[[Variables#BndsRnXp\|BndsRnXp]]</code> in different files named e.g. ''10b.dat, 20b.dat'' etc. for plotting, by putting in separate columns: the energy cutoff; the size of the G blocks; the quasiparticle energy of the valence band; and that of the conduction band.		Once the jobs are terminated we can collect the quasiparticle energies for fixed <code>[[Variables#BndsRnXp\|BndsRnXp]]</code> in different files named e.g. ''10b.dat, 20b.dat'' etc. for plotting, by putting in separate columns: the energy cutoff; the size of the G blocks; the quasiparticle energy of the valence band; and that of the conduction band.
	To do this e.g. for the ''10b.dat'' file you can type:		To do this e.g. for the ''10b.dat'' file you can type:
	$ cat o-10b* \| grep "8~~.000~~" \| awk '{print $3+$4}'		$ cat o-10b* \| grep "7 * 8" \| awk '{print $3+$4}'
	to parse the valence band quasiparticle energies and		to parse the valence band quasiparticle energies and
	$ cat o-10b* \| grep "9~~.000~~" \| awk '{print $3+$4}'		$ cat o-10b* \| grep "7 * 9" \| awk '{print $3+$4}'
	for the conduction band; and put all the data in the ''10b.dat'' files. As there are many files to process you can use the [[bash_scripts\|parse_qps.sh]] script to create the ''10b.dat'' file and edit the script changing the number of <code>[[Variables#BndsRnXp\|BndsRnXp]]</code> for the other output files.		for the conduction band; and put all the data in the ''10b.dat'' files. As there are many files to process you can use the [[bash_scripts\|parse_qps.sh]] script to create the ''10b.dat'' file and edit the script changing the number of <code>[[Variables#BndsRnXp\|BndsRnXp]]</code> for the other output files.

Giacomo.sesti at 13:21, 18 May 2025

2025-05-18T13:21:31Z

← Older revision		Revision as of 13:21, 18 May 2025
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	# K-point Band Eo E-Eo Sc\|Eo		# K-point Band Eo E-Eo Sc\|Eo
	#		#
	7~~.000000~~ 8~~.000000~~ -0.411876 -0.567723 2.322443		7 8 -0.411876 -0.567723 2.322443
	7~~.000000~~ 9~~.000000~~ 3.877976 2.413773 -2.232241		7 9 3.877976 2.413773 -2.232241

	In the header you can see the details of the calculations, for instance it reports that <code>[[Variables#NGsBlkXp\|NGsBlkXp]]</code>=1 Ry corresponds to 5 Gvectors:		In the header you can see the details of the calculations, for instance it reports that <code>[[Variables#NGsBlkXp\|NGsBlkXp]]</code>=1 Ry corresponds to 5 Gvectors:
Line 233:		Line 233:
	and as done before we can inspect the obtained quasiparticle energies:		and as done before we can inspect the obtained quasiparticle energies:

	$ grep 8~~.00~~ o-Gbnd* \| awk '{print $4+$5}'		$ grep "7 * 8" o-Gbnd* \| awk '{print $4+$5}'
	for the valence bands, and		for the valence bands, and
	$ grep 9~~.00~~ o-Gbnd* \| awk '{print $4+$5}'		$ grep "7 * 9" o-Gbnd* \| awk '{print $4+$5}'
	for the conduction band.		for the conduction band.

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	and collect the new results:		and collect the new results:

	$ grep 8~~.000~~ *term.qp \| awk '{print $4+$5}'		$ grep "7 * 8" *term.qp \| awk '{print $4+$5}'
	$ grep 9~~.000~~ *term.qp \| awk '{print $4+$5}'		$ grep "7 * 9" *term.qp \| awk '{print $4+$5}'

	in a new file called ''Gbnd_conv_terminator.dat''. Now we can plot the same quantities as before by looking at the effect of having introduced the terminator.		in a new file called ''Gbnd_conv_terminator.dat''. Now we can plot the same quantities as before by looking at the effect of having introduced the terminator.
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	# K-point Band Eo E-Eo Sc\|Eo		# K-point Band Eo E-Eo Sc\|Eo
	#		#
	7~~.00000~~ 8~~.00000~~ -0.41188 -0.08708 2.91254		7 8 -0.41188 -0.08708 2.91254
	7~~.00000~~ 9~~.00000~~ 3.877976 1.421968 -3.417357		7 9 3.877976 1.421968 -3.417357

	''o-ff100.qp_01'' '''Secant Solver:'''		''o-ff100.qp_01'' '''Secant Solver:'''
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	# K-point Band Eo E-Eo Sc\|Eo		# K-point Band Eo E-Eo Sc\|Eo
	#		#
	7~~.00000~~ 8~~.00000~~ -0.41188 -0.08715 2.93518		7 8 -0.41188 -0.08715 2.93518
	7~~.00000~~ 9~~.00000~~ 3.877976 1.401408 -3.731649		7 9 3.877976 1.401408 -3.731649

Yambowikiadmin: Yambowikiadmin moved page GW tutorial Rome 2023 to GW on h-BN (standalone)

2024-10-15T12:35:18Z

Yambowikiadmin moved page GW tutorial Rome 2023 to GW on h-BN (standalone)

← Older revision	Revision as of 12:35, 15 October 2024
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