LDMATRIX - Revision history

Singraber at 08:10, 24 October 2025

2025-10-24T08:10:16Z

← Older revision		Revision as of 08:10, 24 October 2025
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	----		----

	To compute the zero-field-splitting (ZFS) tensor due to spin-spin interactions in a collinear magnetic calculation ({{~~TAGO~~\|ISPIN\|2}}), set:		To compute the zero-field-splitting (ZFS) tensor due to spin-spin interactions in a collinear magnetic calculation ({{TAG\|ISPIN\|2}}), set:

	{{TAGBL\|LDMATRIX}} = True		{{TAGBL\|LDMATRIX}} = True
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	The ZFS arises from spin-spin interactions between unpaired electrons in a high-spin state with a total spin <math> S \geq 1 </math>. The ZFS matrix, also called D matrix, is measured in electron-spin resonance (ESR) experiments and provides insights into the local electronic environment of defect centers.		The ZFS arises from spin-spin interactions between unpaired electrons in a high-spin state with a total spin <math> S \geq 1 </math>. The ZFS matrix, also called D matrix, is measured in electron-spin resonance (ESR) experiments and provides insights into the local electronic environment of defect centers.

	The implementation follows the formalism of Rayson and Briddon (2008){{Cite\|rayson:prb:2008}}, which efficiently evaluates the spin-spin interaction within periodic density-functional theory (DFT) using reciprocal space methods. This approach avoids expensive six-dimensional real-space integrations, leading to a stable and computationally efficient method. The expressions are similar to integrals used to evaluate the exact exchange energies for [[:Category:Hybrid functionals\|hybrid and HF-type calculation]], hence VASP sets {{~~TAGO~~\|LHFCALC\|True}}. This still allows for simple DFT calculations ({{~~TAGO~~\|AEXX\|0.0}} default), however mind that the default symmetrization is {{~~TAGO~~\|ISYM\|3}}. {{TAG\|LDMATRIX}} should not be combined with {{~~TAGO~~\|ISYM\|1}}, or <code>2</code>.		The implementation follows the formalism of Rayson and Briddon (2008){{Cite\|rayson:prb:2008}}, which efficiently evaluates the spin-spin interaction within periodic density-functional theory (DFT) using reciprocal space methods. This approach avoids expensive six-dimensional real-space integrations, leading to a stable and computationally efficient method. The expressions are similar to integrals used to evaluate the exact exchange energies for [[:Category:Hybrid functionals\|hybrid and HF-type calculation]], hence VASP sets {{TAG\|LHFCALC\|True}}. This still allows for simple DFT calculations ({{TAG\|AEXX\|0.0}} default), however mind that the default symmetrization is {{TAG\|ISYM\|3}}. {{TAG\|LDMATRIX}} should not be combined with {{TAG\|ISYM\|1}}, or <code>2</code>.

	== Output ==		== Output ==
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	* [[Choosing pseudopotentials\|Choice of PAW potentials]]: The ZFS tensor values can be sensitive to the specific [[:Category:Pseudopotentials\|PAW potential]] used, as different [[:Category:Pseudopotentials\|pseudopotentials]] include varying number of electrons in the valence. In particular, it is crucial that the states that give rise to the magnetic moment are included.		* [[Choosing pseudopotentials\|Choice of PAW potentials]]: The ZFS tensor values can be sensitive to the specific [[:Category:Pseudopotentials\|PAW potential]] used, as different [[:Category:Pseudopotentials\|pseudopotentials]] include varying number of electrons in the valence. In particular, it is crucial that the states that give rise to the magnetic moment are included.
	* {{TAG\|NUPDOWN}} tag can be used to obtain a high-spin state.		* {{TAG\|NUPDOWN}} tag can be used to obtain a high-spin state.
	* The {{TAG\|LDMATRIX}} implementation is best tested for <code>vasp_std</code>. A bug for <code>vasp_gam</code> with {{~~TAGO~~\|NCORE\|1\|op=>}} has been fixed, see [[Known_issues#KnownIssue33a\|D-matrix broken for vasp_gam]].		* The {{TAG\|LDMATRIX}} implementation is best tested for <code>vasp_std</code>. A bug for <code>vasp_gam</code> with {{TAG\|NCORE\|1\|op=>}} has been fixed, see [[Known_issues#KnownIssue33a\|D-matrix broken for vasp_gam]].
	{{NB\|warning\| {{TAG\|LDMATRIX}} cannot be used with noncollinear magnetic calculations ({{TAG\|LNONCOLLINEAR}} and/or {{TAG\|LSORBIT}}).\|:}}		{{NB\|warning\| {{TAG\|LDMATRIX}} cannot be used with noncollinear magnetic calculations ({{TAG\|LNONCOLLINEAR}} and/or {{TAG\|LSORBIT}}).\|:}}
	* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: https://vasp.at/forum/viewtopic.php?p=29801p29801		* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: https://vasp.at/forum/viewtopic.php?p=29801p29801

Huebsch at 08:53, 11 February 2025

2025-02-11T08:53:06Z

← Older revision		Revision as of 08:53, 11 February 2025
Line 42:		Line 42:
	* {{TAG\|NUPDOWN}} tag can be used to obtain a high-spin state.		* {{TAG\|NUPDOWN}} tag can be used to obtain a high-spin state.
	* The {{TAG\|LDMATRIX}} implementation is best tested for <code>vasp_std</code>. A bug for <code>vasp_gam</code> with {{TAGO\|NCORE\|1\|op=>}} has been fixed, see [[Known_issues#KnownIssue33a\|D-matrix broken for vasp_gam]].		* The {{TAG\|LDMATRIX}} implementation is best tested for <code>vasp_std</code>. A bug for <code>vasp_gam</code> with {{TAGO\|NCORE\|1\|op=>}} has been fixed, see [[Known_issues#KnownIssue33a\|D-matrix broken for vasp_gam]].
			{{NB\|warning\| {{TAG\|LDMATRIX}} cannot be used with noncollinear magnetic calculations ({{TAG\|LNONCOLLINEAR}} and/or {{TAG\|LSORBIT}}).\|:}}
	* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: https://vasp.at/forum/viewtopic.php?p=29801p29801		* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: https://vasp.at/forum/viewtopic.php?p=29801p29801

Huebsch at 08:39, 11 February 2025

2025-02-11T08:39:25Z

← Older revision		Revision as of 08:39, 11 February 2025
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	* [[Choosing pseudopotentials\|Choice of PAW potentials]]: The ZFS tensor values can be sensitive to the specific [[:Category:Pseudopotentials\|PAW potential]] used, as different [[:Category:Pseudopotentials\|pseudopotentials]] include varying number of electrons in the valence. In particular, it is crucial that the states that give rise to the magnetic moment are included.		* [[Choosing pseudopotentials\|Choice of PAW potentials]]: The ZFS tensor values can be sensitive to the specific [[:Category:Pseudopotentials\|PAW potential]] used, as different [[:Category:Pseudopotentials\|pseudopotentials]] include varying number of electrons in the valence. In particular, it is crucial that the states that give rise to the magnetic moment are included.
	* {{TAG\|NUPDOWN}} tag can be used to obtain a high-spin state.		* {{TAG\|NUPDOWN}} tag can be used to obtain a high-spin state.
	* The {{TAG\|LDMATRIX}} implementation is best tested for <code>vasp_std</code>. A bug for <code>vasp_gam</code> with {{TAGO\|NCORE\|1\|op=>}} has been fixed, see [[Known_issues#~~KnownIssue33~~\|D-matrix broken for vasp_gam]].		* The {{TAG\|LDMATRIX}} implementation is best tested for <code>vasp_std</code>. A bug for <code>vasp_gam</code> with {{TAGO\|NCORE\|1\|op=>}} has been fixed, see [[Known_issues#KnownIssue33a\|D-matrix broken for vasp_gam]].
	* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: https://vasp.at/forum/viewtopic.php?p=29801p29801		* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: https://vasp.at/forum/viewtopic.php?p=29801p29801

Huebsch: Huebsch moved page Construction:LDMATRIX to LDMATRIX without leaving a redirect

2025-02-11T08:33:46Z

Huebsch moved page Construction:LDMATRIX to LDMATRIX without leaving a redirect

← Older revision	Revision as of 08:33, 11 February 2025
(No difference)

Huebsch at 08:33, 11 February 2025

2025-02-11T08:33:29Z

← Older revision		Revision as of 08:33, 11 February 2025
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	== References ==		== References ==

	~~<!--~~[[Category:INCAR tag]][[Category:Electronic ground-state properties]][[Category:Magnetism]]		[[Category:INCAR tag]][[Category:Electronic ground-state properties]][[Category:Magnetism]]

Huebsch at 08:32, 11 February 2025

2025-02-11T08:32:56Z

← Older revision		Revision as of 08:32, 11 February 2025
Line 41:		Line 41:
	* [[Choosing pseudopotentials\|Choice of PAW potentials]]: The ZFS tensor values can be sensitive to the specific [[:Category:Pseudopotentials\|PAW potential]] used, as different [[:Category:Pseudopotentials\|pseudopotentials]] include varying number of electrons in the valence. In particular, it is crucial that the states that give rise to the magnetic moment are included.		* [[Choosing pseudopotentials\|Choice of PAW potentials]]: The ZFS tensor values can be sensitive to the specific [[:Category:Pseudopotentials\|PAW potential]] used, as different [[:Category:Pseudopotentials\|pseudopotentials]] include varying number of electrons in the valence. In particular, it is crucial that the states that give rise to the magnetic moment are included.
	* {{TAG\|NUPDOWN}} tag can be used to obtain a high-spin state.		* {{TAG\|NUPDOWN}} tag can be used to obtain a high-spin state.
	* The {{TAG\|LDMATRIX}} implementation is tested for <code>vasp_std</code>. ~~Using~~ <code>vasp_gam</code> has been ~~found to yield incorrect results due to missing integral evaluations~~.		* The {{TAG\|LDMATRIX}} implementation is best tested for <code>vasp_std</code>. A bug for <code>vasp_gam</code> with {{TAGO\|NCORE\|1\|op=>}} has been fixed, see [[Known_issues#KnownIssue33\|D-matrix broken for vasp_gam]].
	* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: [https://vasp.at/forum/viewtopic.php?p=29801p29801]		* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: https://vasp.at/forum/viewtopic.php?p=29801p29801

	== Related tags an articles ==		== Related tags an articles ==

Huebsch at 08:06, 11 February 2025

2025-02-11T08:06:10Z

← Older revision		Revision as of 08:06, 11 February 2025
Line 11:		Line 11:
	The ZFS arises from spin-spin interactions between unpaired electrons in a high-spin state with a total spin <math> S \geq 1 </math>. The ZFS matrix, also called D matrix, is measured in electron-spin resonance (ESR) experiments and provides insights into the local electronic environment of defect centers.		The ZFS arises from spin-spin interactions between unpaired electrons in a high-spin state with a total spin <math> S \geq 1 </math>. The ZFS matrix, also called D matrix, is measured in electron-spin resonance (ESR) experiments and provides insights into the local electronic environment of defect centers.

	The implementation follows the formalism of Rayson and Briddon (2008){{Cite\|rayson:prb:2008}}, which efficiently evaluates the spin-spin interaction within periodic density-functional theory (DFT) using reciprocal space methods. This approach avoids expensive six-dimensional real-space integrations, leading to a stable and computationally efficient method. The expressions are similar to integrals used to evaluate the exact exchange energies for [[:Category:Hybrid functionals\|hybrid and HF-type calculation]], hence VASP sets {{TAGO\|LHFCALC\|True}}. This still allows for simple DFT calculations ({{TAGO\|AEXX\|0.0}} default), however mind that the default symmetrization is {{TAGO\|ISYM\|3}}. {{TAG\|LDMATRIX}} should not be combined with {{~~TAG~~\|ISYM\|1}}, or <code>2</code>.		The implementation follows the formalism of Rayson and Briddon (2008){{Cite\|rayson:prb:2008}}, which efficiently evaluates the spin-spin interaction within periodic density-functional theory (DFT) using reciprocal space methods. This approach avoids expensive six-dimensional real-space integrations, leading to a stable and computationally efficient method. The expressions are similar to integrals used to evaluate the exact exchange energies for [[:Category:Hybrid functionals\|hybrid and HF-type calculation]], hence VASP sets {{TAGO\|LHFCALC\|True}}. This still allows for simple DFT calculations ({{TAGO\|AEXX\|0.0}} default), however mind that the default symmetrization is {{TAGO\|ISYM\|3}}. {{TAG\|LDMATRIX}} should not be combined with {{TAGO\|ISYM\|1}}, or <code>2</code>.

	== Output ==		== Output ==

Huebsch: Created page with "{{TAGDEF|LDMATRIX|.TRUE. {{!}} .FALSE. | .FALSE.}} Description: Computes the zero-field splitting (ZFS) matrix. ---- To compute the zero-field-splitting (ZFS) tensor due to spin-spin interactions in a collinear magnetic calculation ({{TAGO|ISPIN|2}}), set: {{TAGBL|LDMATRIX}} = True # sets default {{TAGBL|LHFCALC}} = True ; {{TAGBL|AEXX}}=0.0 The ZFS arises from spin-spin interactions between unpaired electrons in a high-spin state with a total spin $S \ge..."$

2025-02-11T08:04:57Z

Created page with "{{TAGDEF|LDMATRIX|.TRUE. {{!}} .FALSE. | .FALSE.}} Description: Computes the zero-field splitting (ZFS) matrix. ---- To compute the zero-field-splitting (ZFS) tensor due to spin-spin interactions in a collinear magnetic calculation ({{TAGO|ISPIN|2}}), set: {{TAGBL|LDMATRIX}} = True # sets default {{TAGBL|LHFCALC}} = True ; {{TAGBL|AEXX}}=0.0 The ZFS arises from spin-spin interactions between unpaired electrons in a high-spin state with a total spin <math> S \ge..."

New page

{{TAGDEF|LDMATRIX|.TRUE. {{!}} .FALSE. | .FALSE.}}

Description: Computes the zero-field splitting (ZFS) matrix.
----

To compute the zero-field-splitting (ZFS) tensor due to spin-spin interactions in a collinear magnetic calculation ({{TAGO|ISPIN|2}}), set:

{{TAGBL|LDMATRIX}} = True
# sets default {{TAGBL|LHFCALC}} = True ; {{TAGBL|AEXX}}=0.0

The ZFS arises from spin-spin interactions between unpaired electrons in a high-spin state with a total spin <math> S \geq 1 </math>. The ZFS matrix, also called D matrix, is measured in electron-spin resonance (ESR) experiments and provides insights into the local electronic environment of defect centers.

The implementation follows the formalism of Rayson and Briddon (2008){{Cite|rayson:prb:2008}}, which efficiently evaluates the spin-spin interaction within periodic density-functional theory (DFT) using reciprocal space methods. This approach avoids expensive six-dimensional real-space integrations, leading to a stable and computationally efficient method. The expressions are similar to integrals used to evaluate the exact exchange energies for [[:Category:Hybrid functionals|hybrid and HF-type calculation]], hence VASP sets {{TAGO|LHFCALC|True}}. This still allows for simple DFT calculations ({{TAGO|AEXX|0.0}} default), however mind that the default symmetrization is {{TAGO|ISYM|3}}. {{TAG|LDMATRIX}} should not be combined with {{TAG|ISYM|1}}, or <code>2</code>.

== Output ==
The computed zero-field splitting is written in MHz to the stdout:

Jij: -0.0003356 0.0003475 -0.0000119 965.1231107 965.1238969 965.1238508
-Kij: -0.0002748 -0.0000059 0.0002807 64.8471208 64.8472015 64.8471523
D1c: -0.0000541 0.0000275 0.0000267 11.1897131 11.1897125 11.1897272

and the {{FILE|OUTCAR}} file:

Spin-spin contribution to zero-field splitting tensor (MHz)
---------------------------------------------------------------
D_xx D_yy D_zz D_xy D_xz D_yz
---------------------------------------------------------------
0.001 0.000 -0.001 1042.316 1020.260 1041.130
---------------------------------------------------------------

after diagonalization
---------------------------------------------
D_diag eigenvector (x,y,z)
---------------------------------------------
-1020.244 -0.697 -0.019 0.717
-1048.926 -0.427 0.814 -0.393
2069.171 -0.576 -0.580 -0.576
---------------------------------------------

== Advice ==
* [[Choosing pseudopotentials|Choice of PAW potentials]]: The ZFS tensor values can be sensitive to the specific [[:Category:Pseudopotentials|PAW potential]] used, as different [[:Category:Pseudopotentials|pseudopotentials]] include varying number of electrons in the valence. In particular, it is crucial that the states that give rise to the magnetic moment are included.
* {{TAG|NUPDOWN}} tag can be used to obtain a high-spin state.
* The {{TAG|LDMATRIX}} implementation is tested for <code>vasp_std</code>. Using <code>vasp_gam</code> has been found to yield incorrect results due to missing integral evaluations.
* Spin-contamination corrections: Some users have modified the source code to include spin-contamination corrections, particularly for low-spin states (<math>S=0</math>). These modifications are ''not'' included in the default VASP version but can be implemented manually. See forum discussion: [https://vasp.at/forum/viewtopic.php?p=29801p29801]

== Related tags an articles ==
{{TAG|LHFCALC}}, {{TAG|NUPDOWN}}, {{TAG|ISPIN}}

== References ==

<!--[[Category:INCAR tag]][[Category:Electronic ground-state properties]][[Category:Magnetism]]