Dielectric properties of Si using BSE - Revision history

Karsai: /* Download */

2019-11-14T13:20:59Z

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← Older revision		Revision as of 13:20, 14 November 2019
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	{{Template:BSE}}		{{Template:BSE}}
	~~Back to the [[The_VASP_Manual\|main page]]~~

	[[Category:Examples]]		[[Category:Examples]]

2019-11-14T08:01:04Z

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2019-11-14T08:00:52Z

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← Older revision		Revision as of 08:00, 14 November 2019
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	== Download ==		== Download ==
	[~~http://www.vasp.at/vasp-workshop/examples/Si_BSE~~.tgz Si_BSE.tgz]		[[Si BSE.tgz\| Si_BSE.tgz]]

	{{Template:BSE}}		{{Template:BSE}}

2019-06-07T13:19:29Z

2017-12-13T16:35:30Z

Step 5: The BSE calculation

← Older revision		Revision as of 16:35, 13 December 2017
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	=== Step 5: The BSE calculation ===		=== Step 5: The BSE calculation ===
	* This step uses the INCAR.BSE file:		* This step uses the INCAR.BSE file:
	[[TAGBL\|PREC}} = Normal ; {{TAGBL\|ENCUT}} = 250.0		{{TAGBL\|PREC}} = Normal ; {{TAGBL\|ENCUT}} = 250.0
	{{TAGBL\|ALGO}} = BSE		{{TAGBL\|ALGO}} = BSE
	{{TAGBL\|ANTIRES}} = 0		{{TAGBL\|ANTIRES}} = 0

2017-12-13T16:35:15Z

Step 3: RPA quasiparticles with single-shot GW (G0W0)

← Older revision		Revision as of 16:35, 13 December 2017
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	{{TAGBL\|LWAVE}} = .TRUE.		{{TAGBL\|LWAVE}} = .TRUE.
	{{TAGBL\|PRECFOCK}} = Normal		{{TAGBL\|PRECFOCK}} = Normal
	*We select the G0W0 method by specifying {{TAG\|ALGO}}=''GW0'' and {TAG\|NELM}}=1.		*We select the G0W0 method by specifying {{TAG\|ALGO}}=''GW0'' and {{TAG\|NELM}}=1.
	*The energy cut off for the response function is select by {{TAG\|ENCUTGW}}.		*The energy cut off for the response function is select by {{TAG\|ENCUTGW}}.
	*The number of point used in the frequency integration is given by {{TAG\|NOMEGA}}.		*The number of point used in the frequency integration is given by {{TAG\|NOMEGA}}.
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	k-point 1 : 0.0000 0.0000 0.0000		k-point 1 : 0.0000 0.0000 0.0000
	band No. KS-energies QP-energies sigma(KS) V_xc(KS) V^pw_x(r,r') Z occupation		band No. KS-energies QP-energies sigma(KS) V_xc(KS) V^pw_x(r,r') Z occupation

	=== Step 4 (optional): Plot IPA dielectric function using GW0 quasiparticle energies ===		=== Step 4 (optional): Plot IPA dielectric function using GW0 quasiparticle energies ===

2017-11-21T11:20:07Z

← Older revision		Revision as of 11:20, 21 November 2017
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	----		----

	~~== Used INCAR Tags ==~~
	{{TAG\|ALGO}}, {{TAG\|ANTIRES}}, {{TAG\|EDIFF}}, {{TAG\|ENCUT}}, {{TAG\|ENCUTGW}}, {{TAG\|IALGO}}, {{TAG\|IMIX}}, {{TAG\|ISMEAR}}, {{TAG\|KPAR}}, {{TAG\|LOPTICS}}, {{TAG\|LPEAD}}, {{TAG\|LWAVE}}, {{TAG\|NBANDS}}, {{TAG\|NBANDSGW}}, {{TAG\|NBANDSO}}, {{TAG\|NBANDSV}}, {{TAG\|NELM}}, {{TAG\|NKRED}}, {{TAG\|NOMEGA}}, {{TAG\|OMEGAMAX}}, {{TAG\|OMEGATL}}, {{TAG\|PREC}}, {{TAG\|PRECFOCK}}, {{TAG\|SIGMA}}

	== Download ==		== Download ==

2017-11-20T15:52:45Z

Step 5: The BSE calculation

← Older revision		Revision as of 15:52, 20 November 2017
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	[[File:Fig BSE example1 2.png\|600px]]		[[File:Fig BSE example1 2.png\|600px]]
	*The calculated dielectric function of Si is at this point (GW+BSE) already in much better agreement with experiment. However we can do even better as shown in the following figure:		*The calculated dielectric function of Si is at this point (GW+BSE) already in much better agreement with experiment. However we can do even better as shown in the following figure:
	[[File:Fig BSE example1 4.png\|~~600px~~]]		[[File:Fig BSE example1 4.png\|400px]]
	*The problem comes from the coarse k-point grid that we have used. A denser grid samples more (direct) transitions between the bands.		*The problem comes from the coarse k-point grid that we have used. A denser grid samples more (direct) transitions between the bands.
	[[File:Fig BSE example1 3.png\|~~400px~~]]		[[File:Fig BSE example1 3.png\|200px]]
	*Simply using a denser grid is mostly not an option because of the computational expense.		*Simply using a denser grid is mostly not an option because of the computational expense.

2017-11-20T15:52:30Z

Step 5: The BSE calculation

← Older revision		Revision as of 15:52, 20 November 2017
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	*By using the script ./plotall.sh we get the absorption spectra within the independent particle picture and with BSE:		*By using the script ./plotall.sh we get the absorption spectra within the independent particle picture and with BSE:
	[[File:Fig BSE example1 2.png\|600px]]		[[File:Fig BSE example1 2.png\|600px]]
			*The calculated dielectric function of Si is at this point (GW+BSE) already in much better agreement with experiment. However we can do even better as shown in the following figure:
			[[File:Fig BSE example1 4.png\|600px]]
			*The problem comes from the coarse k-point grid that we have used. A denser grid samples more (direct) transitions between the bands.
			[[File:Fig BSE example1 3.png\|400px]]
			*Simply using a denser grid is mostly not an option because of the computational expense.

	----		----

2017-11-20T15:49:02Z

← Older revision		Revision as of 15:49, 20 November 2017
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	*This calculation needs the orbitals ({{TAG\|WAVECAR}} file) from step 3 and the derivative of the orbitals with respect to the Bloch vectors ({{TAG\|WAVEDER}} file) written in step 2.		*This calculation needs the orbitals ({{TAG\|WAVECAR}} file) from step 3 and the derivative of the orbitals with respect to the Bloch vectors ({{TAG\|WAVEDER}} file) written in step 2.
	*By using the script ./plotall.sh we get the absorption spectra within the independent particle picture and with BSE:		*By using the script ./plotall.sh we get the absorption spectra within the independent particle picture and with BSE:
	[[File:Fig BSE example1 2.png]]		[[File:Fig BSE example1 2.png\|600px]]