CRPA of SrVO3 - Revision history

Csheldon: /* Optional: Analytic continuation */

2026-02-19T08:47:29Z

Optional: Analytic continuation

← Older revision		Revision as of 08:47, 19 February 2026
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	[[File:SrVO3 U omega acont.png\|480px]]		[[File:SrVO3 U omega acont.png\|480px]]
	{{NB\|tip\|Increase {{TAG\|NOMEGA}} points to resolve more details on the real frequency axis.}}		{{NB\|tip\|Increase {{TAG\|NOMEGA}} points to resolve more details on the real frequency axis.}}
	In the above plot, there are 24 ~~omega~~ points in the calculation, rather than 8 used in the rest of the exercise. The exact features of the graph will change depending on how you fit it using the [https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.AAA.html AAA algorithm] (a rational approximation algorithm). The tolerance parameter <code>rtol</code> can lead to Froissart doublets {{cite\|gilewicz:kryakin:2003}}, i.e., non-physical poles, if <code>rtol</code> is set too tight, e.g., the pole at <math>\omega \approx 13</math> eV. The parameter should be changed in order to ensure that the poles do not disappear when it is modified. The key parts of the graph are the value of the Coulomb potential at <math>\omega = 0</math> eV, the first plasmon peak at <math>\omega \approx 4</math> eV, and that the screened Coulomb potential U approaches the bare Coulomb potential V at high frequencies. Note that the first plasmon peak is approximately the distance between the centers of mass of the p and d states around the Fermi energy, shown in the DOS in the previous exercise.		In the above plot, there are 24 {{TAG\|NOMEGA}} points in the calculation to resolve more detail, rather than 8 used in the rest of the exercise. The exact features of the graph will change depending on how you fit it using the [https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.AAA.html AAA algorithm] (a rational approximation algorithm). The tolerance parameter <code>rtol</code> can lead to Froissart doublets {{cite\|gilewicz:kryakin:2003}}, i.e., non-physical poles, if <code>rtol</code> is set too tight, e.g., the pole at <math>\omega \approx 13</math> eV. The parameter should be changed in order to ensure that the poles do not disappear when it is modified. The key parts of the graph are the value of the Coulomb potential at <math>\omega = 0</math> eV, the first plasmon peak at <math>\omega \approx 4</math> eV, and that the screened Coulomb potential U approaches the bare Coulomb potential V at high frequencies. Note that the first plasmon peak is approximately the distance between the centers of mass of the p and d states around the Fermi energy, shown in the DOS in the previous exercise.

	== Off-centre Coulomb integrals ==		== Off-centre Coulomb integrals ==

Csheldon: /* Optional: Analytic continuation */

2026-02-19T08:45:26Z

Optional: Analytic continuation

← Older revision		Revision as of 08:45, 19 February 2026
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	[[File:SrVO3 U omega acont.png\|480px]]		[[File:SrVO3 U omega acont.png\|480px]]
	{{NB\|tip\|Increase {{TAG\|NOMEGA}} points to resolve more details on the real frequency axis.}}		{{NB\|tip\|Increase {{TAG\|NOMEGA}} points to resolve more details on the real frequency axis.}}
	~~<!--~~In the above plot, there are 24 omega points in the calculation, rather than 8 used in the rest of the exercise. The exact features of the graph will change depending on how you fit it using the [https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.AAA.html AAA algorithm] (a rational approximation algorithm). The tolerance parameter <code>rtol</code> can lead to Froissart doublets {{cite\|gilewicz:kryakin:2003}}, i.e., non-physical poles, if <code>rtol</code> is set too tight, e.g., the pole at <math>\omega \approx 13</math> eV. The parameter should be changed in order to ensure that the poles do not disappear when it is modified. The key parts of the graph are the value of the Coulomb potential at <math>\omega = 0</math> eV, the first plasmon peak at <math>\omega \approx 4</math> eV, and that the screened Coulomb potential U approaches the bare Coulomb potential V at high frequencies. Note that the first plasmon peak is approximately the distance between the centers of mass of the p and d states around the Fermi energy, shown in the DOS in the previous exercise.~~-->~~		In the above plot, there are 24 omega points in the calculation, rather than 8 used in the rest of the exercise. The exact features of the graph will change depending on how you fit it using the [https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.AAA.html AAA algorithm] (a rational approximation algorithm). The tolerance parameter <code>rtol</code> can lead to Froissart doublets {{cite\|gilewicz:kryakin:2003}}, i.e., non-physical poles, if <code>rtol</code> is set too tight, e.g., the pole at <math>\omega \approx 13</math> eV. The parameter should be changed in order to ensure that the poles do not disappear when it is modified. The key parts of the graph are the value of the Coulomb potential at <math>\omega = 0</math> eV, the first plasmon peak at <math>\omega \approx 4</math> eV, and that the screened Coulomb potential U approaches the bare Coulomb potential V at high frequencies. Note that the first plasmon peak is approximately the distance between the centers of mass of the p and d states around the Fermi energy, shown in the DOS in the previous exercise.

	== Off-centre Coulomb integrals ==		== Off-centre Coulomb integrals ==

Csheldon: /* Optional: Analytic continuation */

2026-02-18T13:03:00Z

Optional: Analytic continuation

← Older revision		Revision as of 13:03, 18 February 2026
Line 262:		Line 262:
	[[File:SrVO3 U omega acont.png\|480px]]		[[File:SrVO3 U omega acont.png\|480px]]
	{{NB\|tip\|Increase {{TAG\|NOMEGA}} points to resolve more details on the real frequency axis.}}		{{NB\|tip\|Increase {{TAG\|NOMEGA}} points to resolve more details on the real frequency axis.}}
	<!--In the above plot, there are 24 omega points in the calculation, rather than 8 used in the rest of the exercise. The exact features of the graph will change depending on how you fit it using the [https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.AAA.html AAA algorithm] (a rational approximation algorithm). The tolerance parameter <code>rtol</code> can lead to Froissart doublets {{cite\|gilewicz:kryakin:2003}}, i.e., non-physical poles, if <code>rtol</code> is set too tight, e.g., the pole at <math>\omega \approx 13</math> eV. The parameter should be changed in order to ensure that the poles do not disappear when it is modified. The key parts of the graph are the value of the Coulomb potential at <math>\omega = 0</math> eV, the first plasmon peak at <math>\omega \approx 4</math> eV, and that the screened Coulomb potential U approaches the bare Coulomb potential V at high frequencies.-->		<!--In the above plot, there are 24 omega points in the calculation, rather than 8 used in the rest of the exercise. The exact features of the graph will change depending on how you fit it using the [https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.AAA.html AAA algorithm] (a rational approximation algorithm). The tolerance parameter <code>rtol</code> can lead to Froissart doublets {{cite\|gilewicz:kryakin:2003}}, i.e., non-physical poles, if <code>rtol</code> is set too tight, e.g., the pole at <math>\omega \approx 13</math> eV. The parameter should be changed in order to ensure that the poles do not disappear when it is modified. The key parts of the graph are the value of the Coulomb potential at <math>\omega = 0</math> eV, the first plasmon peak at <math>\omega \approx 4</math> eV, and that the screened Coulomb potential U approaches the bare Coulomb potential V at high frequencies. Note that the first plasmon peak is approximately the distance between the centers of mass of the p and d states around the Fermi energy, shown in the DOS in the previous exercise.-->

	== Off-centre Coulomb integrals ==		== Off-centre Coulomb integrals ==

Csheldon: /* Optional: Analytic continuation */

2026-02-18T12:59:26Z

Optional: Analytic continuation

← Older revision		Revision as of 12:59, 18 February 2026
Line 262:		Line 262:
	[[File:SrVO3 U omega acont.png\|480px]]		[[File:SrVO3 U omega acont.png\|480px]]
	{{NB\|tip\|Increase {{TAG\|NOMEGA}} points to resolve more details on the real frequency axis.}}		{{NB\|tip\|Increase {{TAG\|NOMEGA}} points to resolve more details on the real frequency axis.}}
			<!--In the above plot, there are 24 omega points in the calculation, rather than 8 used in the rest of the exercise. The exact features of the graph will change depending on how you fit it using the [https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.AAA.html AAA algorithm] (a rational approximation algorithm). The tolerance parameter <code>rtol</code> can lead to Froissart doublets {{cite\|gilewicz:kryakin:2003}}, i.e., non-physical poles, if <code>rtol</code> is set too tight, e.g., the pole at <math>\omega \approx 13</math> eV. The parameter should be changed in order to ensure that the poles do not disappear when it is modified. The key parts of the graph are the value of the Coulomb potential at <math>\omega = 0</math> eV, the first plasmon peak at <math>\omega \approx 4</math> eV, and that the screened Coulomb potential U approaches the bare Coulomb potential V at high frequencies.-->

	== Off-centre Coulomb integrals ==		== Off-centre Coulomb integrals ==

Csheldon: /* Downloads */

2026-01-29T09:02:17Z

Downloads

← Older revision		Revision as of 09:02, 29 January 2026
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	Back to the [[The_VASP_Manual\|main page]].		Back to the [[The_VASP_Manual\|main page]].

			== References ==

	[[Category:Examples]][[Category:Constrained-random-phase approximation]]		[[Category:Examples]][[Category:Constrained-random-phase approximation]]

Csheldon: /* Off-centre Coulomb integrals */

2026-01-29T09:01:48Z

Off-centre Coulomb integrals

← Older revision		Revision as of 09:01, 29 January 2026
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	== Off-centre Coulomb integrals ==		== Off-centre Coulomb integrals ==
			{{Available\|6.6.0}}
	Every cRPA job writes the effectively screened Coulomb kernel (in reciprocal space) at zero frequency to {{FILE\|WFULLxxxx.tmp}} files.		Every cRPA job writes the effectively screened Coulomb kernel (in reciprocal space) at zero frequency to {{FILE\|WFULLxxxx.tmp}} files.
	These files can be read in and off-centre Coulomb integrals can be evaluated using following input:		These files can be read in and off-centre Coulomb integrals can be evaluated using following input:
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	2 1 1 1 0.0000021144 0.0000002295		2 1 1 1 0.0000021144 0.0000002295
	...		...
	~~{{NB\|mind\|Available as of VASP.6.5.2.}}~~

	== Downloads ==		== Downloads ==

Csheldon: /* cRPA calculation on Matsubara axis */

2026-01-29T09:01:39Z

cRPA calculation on Matsubara axis

← Older revision		Revision as of 09:01, 29 January 2026
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	=== cRPA calculation on Matsubara axis ===		=== cRPA calculation on Matsubara axis ===
	{{NB\|~~mind\|Available as of VASP~~.6.~~5.2.~~}}		{{Available\|6.6.0}}
	Note that the same frequency grid is used as for {{TAG\|ALGO}}=RPA (RPA correlation energy calculation) and can not be changed directly.		Note that the same frequency grid is used as for {{TAG\|ALGO}}=RPA (RPA correlation energy calculation) and can not be changed directly.
	To calculate the cRPA interaction for a set of automatically chosen imaginary frequency points use once again the PBE wavefunction as input		To calculate the cRPA interaction for a set of automatically chosen imaginary frequency points use once again the PBE wavefunction as input

Csheldon: /* cRPA Calculation */

2026-01-22T16:01:03Z

cRPA Calculation

← Older revision		Revision as of 16:01, 22 January 2026
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	# and omit the definition of an energy window like so		# and omit the definition of an energy window like so
	exclude_bands = 1-20, 24-96		exclude_bands = 1-20, 24-96

	begin projections		begin projections
	V:dxy;dxz;dyz		V:dxy;dxz;dyz

Kaltakm: /* Off-centre Coulomb integrals */

2025-10-13T01:22:53Z

Off-centre Coulomb integrals

← Older revision		Revision as of 01:22, 13 October 2025
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	{{TAGBL\|SIGMA}} = 0.1 # electronic temperature		{{TAGBL\|SIGMA}} = 0.1 # electronic temperature
	{{TAGBL\|NBANDS}} = 96 # use same number of bands as stored in WAVECAR		{{TAGBL\|NBANDS}} = 96 # use same number of bands as stored in WAVECAR
	~~{{TAGBL\|ALGO}} = 2E4WA # Compute off-centre Coulomb integrals~~
	{{TAGBL\|PRECFOCK}} = Fast # fast mode for FFTs		{{TAGBL\|PRECFOCK}} = Fast # fast mode for FFTs
	{{TAGBL\|NTARGET_STATES}} = 1 2 3 # Wannier states for which Coulomb integrals are evaluated		{{TAGBL\|NTARGET_STATES}} = 1 2 3 # Wannier states for which Coulomb integrals are evaluated

Kaltakm: /* cRPA Calculation */

2025-03-28T09:10:08Z

cRPA Calculation

← Older revision		Revision as of 09:10, 28 March 2025
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	screened Hubbard u = 2.3455 0.0000		screened Hubbard u = 2.3455 0.0000
	screened Hubbard J = 0.4281 -0.0000		screened Hubbard J = 0.4281 -0.0000
			The full interaction matrix is written to {{FILE\|UIJKL}}.
	{{NB\|mind\|The frequency point <math>\omega</math> can be set by {{TAG\|OMEGAMAX}} in the INCAR.}}		{{NB\|mind\|The frequency point <math>\omega</math> can be set by {{TAG\|OMEGAMAX}} in the INCAR.}}
	For instance to evaluate the cRPA interaction matrix at <math>\omega=10</math> eV, add		For instance to evaluate the cRPA interaction matrix at <math>\omega=10</math> eV, add
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	bare Hubbard u = 15.0984 -0.0000		bare Hubbard u = 15.0984 -0.0000
	bare Hubbard J = 0.5351 0.0000		bare Hubbard J = 0.5351 0.0000
			Similar to the effectively screened interaction the full output is written to {{FILE\|VIJKL}}.

	=== cRPA calculation on Matsubara axis ===		=== cRPA calculation on Matsubara axis ===

← Older revision		Revision as of 01:22, 13 October 2025
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	{{TAGBL\|SIGMA}} = 0.1 # electronic temperature		{{TAGBL\|SIGMA}} = 0.1 # electronic temperature
	{{TAGBL\|NBANDS}} = 96 # use same number of bands as stored in WAVECAR		{{TAGBL\|NBANDS}} = 96 # use same number of bands as stored in WAVECAR
	~~{{TAGBL\|ALGO}} = 2E4WA # Compute off-centre Coulomb integrals~~
	{{TAGBL\|PRECFOCK}} = Fast # fast mode for FFTs		{{TAGBL\|PRECFOCK}} = Fast # fast mode for FFTs
	{{TAGBL\|NTARGET_STATES}} = 1 2 3 # Wannier states for which Coulomb integrals are evaluated		{{TAGBL\|NTARGET_STATES}} = 1 2 3 # Wannier states for which Coulomb integrals are evaluated