Orthorhombic charge density wave on the tetragonal lattice of EuAl4

Authors:

Sitaram Ramakrishnan; Surya Rohith Kotla; Toms Rekis; Jin-Ke Bao; Claudio Eisele; Leila Noohinejad; Martin Tolkiehn; Carsten Paulmann; Birender Singh; Rahul Verma; Biplab Bag; Ruta Kulkarni; Arumugam Thamizhavel; Bahadur Singh; Srinivasan Ramakrishnan; Sander van Smaalen

Journal:

IUCrJ 9 378-385 (2022)

DOI:

https://doi.org/10.1107/S2052252522003888

B-IncStrDB ID: KGB6B0qsuYG Entry date: 2022-04-24 Last revision: 2022-05-21

I

Chemical data


Common Name: EuAl4 [ Help ]

Structural Formula Sum: Al4 Eu1 [ Help ]

Formula weight: 259.9 Da [ Help ]

Absolute configuration: . [ Help ]

Crystallographic data and experimental details


Crystal system: tetragonal [ Help ]

Space group name (H-M): I 4/m m m [ Help ]

Space group name (Hall): -I 4;-2 [ Help ]

Space group nb.: 139 [ Help ]

Symmetry operations of the space group: [ Help ]

Operation code Operation in algebraic form
1 x,y,z
2 -x,-y,z
3 -y,x,z
4 y,-x,z
5 -x,y,-z
6 x,-y,-z
7 y,x,-z
8 -y,-x,-z
9 -x,-y,-z
10 x,y,-z
11 y,-x,-z
12 -y,x,-z
13 x,-y,z
14 -x,y,z
15 -y,-x,z
16 y,x,z
17 x+1/2,y+1/2,z+1/2
18 -x+1/2,-y+1/2,z+1/2
19 -y+1/2,x+1/2,z+1/2
20 y+1/2,-x+1/2,z+1/2
21 -x+1/2,y+1/2,-z+1/2
22 x+1/2,-y+1/2,-z+1/2
23 y+1/2,x+1/2,-z+1/2
24 -y+1/2,-x+1/2,-z+1/2
25 -x+1/2,-y+1/2,-z+1/2
26 x+1/2,y+1/2,-z+1/2
27 y+1/2,-x+1/2,-z+1/2
28 -y+1/2,x+1/2,-z+1/2
29 x+1/2,-y+1/2,z+1/2
30 -x+1/2,y+1/2,z+1/2
31 -y+1/2,-x+1/2,z+1/2
32 y+1/2,x+1/2,z+1/2

a: 4.39490(10) Å [ Help ]

b: 4.39490(10) Å [ Help ]

c: 11.1607(3) Å [ Help ]

α: 90 ° [ Help ]

β: 90 ° [ Help ]

γ: 90 ° [ Help ]

Volume: 215.571(9) Å3 [ Help ]

Z: 2 [ Help ]

Cell determination reflection Nb.: 1000 [ Help ]

θ(min) for cell determination: 1.5 ° [ Help ]

θ(max) for cell determination: 20 ° [ Help ]

Cell measurement temperature: 250 K [ Help ]

μ: 5.873 mm-1 [ Help ]

Absorption correction type: empirical [ Help ]

Absorption correction remarks: SADABS, Program for Empirical Absorption Correction of Area Detector Data, G. M. Sheldrick, 1996 [ Help ]

Minimum transmission factor: 0.3211 [ Help ]

Maximum transmission factor: 0.3712 [ Help ]

Refinement details


Refinement remarks: ? [ Help ]

Total nb. of reflections: 109 [ Help ]

Nb. of observed reflections: 109 [ Help ]

Intense reflections threshold: I>3σ(I) [ Help ]

Refinement based on: F [ Help ]

R(obs): 0.0147 [ Help ]

wR(obs): 0.0214 [ Help ]

R(all): 0.0147 [ Help ]

wR(all): 0.0214 [ Help ]

S(all): 1.53 [ Help ]

S(obs): 1.53 [ Help ]

Nb. of reflections: 109 [ Help ]

Nb. of parameters: 9 [ Help ]

Number of restraints: 0 [ Help ]

Number of constraints: 0 [ Help ]

Weighting scheme: sigma [ Help ]

Weighting scheme remarks: w=1/(σ2(F)+0.0001F2) [ Help ]

Δ/σ(max): 0.0001 [ Help ]

Δ/σ(mean): 0.0000 [ Help ]

Δρ(max): 1.15 e_Å-3 [ Help ]

Δρ(min): -1.35 e_Å-3 [ Help ]

Extinction method: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974) [ Help ]

Extinction coefficient: 80(70) [ Help ]

Structural Information


Average Structure: [ Help ]

Atom site label Atom symbol x y z ADP type Uiso/equiv Symmetry multiplicity Occupancy Coords from (d)iffraction or (c)alculated Coords restraints or constraints Disordered cluster Disordered group
Eu1 Eu 0 0 0 Uani 0.0098(2) 2 1 d . . .
Al1 Al 0 0.5 0.25 Uani 0.0107(5) 4 1 d . . .
Al2 Al 0 0 0.3849(2) Uani 0.0102(5) 4 1 d . . .

ADP components: [ Help ]

Atom site label Atom site symbol U11 U22 U33 U12 U13 U23
Eu1 Eu 0.0083(3) 0.0083(3) 0.0126(4) 0 0 0
Al1 Al 0.0112(8) 0.0112(8) 0.0098(10) 0 0 0
Al2 Al 0.0103(8) 0.0103(8) 0.0099(10) 0 0 0

II

Chemical data


Common Name: EuAl4 [ Help ]

Structural Formula Sum: Al4 Eu1 [ Help ]

Formula weight: 259.9 Da [ Help ]

Absolute configuration: . [ Help ]

Crystallographic data and experimental details


Crystal system: orthorhombic [ Help ]

Superspace group name: Fmmm(00γ)s00 [ Help ]

Symmetry operations of the superspace group: [ Help ]

Operation code Operation in algebraic form
1 x1,x2,x3,x4
2 -x1,-x2,x3,x4+1/2
3 -x1,x2,-x3,-x4
4 x1,-x2,-x3,-x4+1/2
5 -x1,-x2,-x3,-x4
6 x1,x2,-x3,-x4+1/2
7 x1,-x2,x3,x4
8 -x1,x2,x3,x4+1/2
9 x1,x2+1/2,x3+1/2,x4
10 -x1,-x2+1/2,x3+1/2,x4+1/2
11 -x1,x2+1/2,-x3+1/2,-x4
12 x1,-x2+1/2,-x3+1/2,-x4+1/2
13 -x1,-x2+1/2,-x3+1/2,-x4
14 x1,x2+1/2,-x3+1/2,-x4+1/2
15 x1,-x2+1/2,x3+1/2,x4
16 -x1,x2+1/2,x3+1/2,x4+1/2
17 x1+1/2,x2,x3+1/2,x4
18 -x1+1/2,-x2,x3+1/2,x4+1/2
19 -x1+1/2,x2,-x3+1/2,-x4
20 x1+1/2,-x2,-x3+1/2,-x4+1/2
21 -x1+1/2,-x2,-x3+1/2,-x4
22 x1+1/2,x2,-x3+1/2,-x4+1/2
23 x1+1/2,-x2,x3+1/2,x4
24 -x1+1/2,x2,x3+1/2,x4+1/2
25 x1+1/2,x2+1/2,x3,x4
26 -x1+1/2,-x2+1/2,x3,x4+1/2
27 -x1+1/2,x2+1/2,-x3,-x4
28 x1+1/2,-x2+1/2,-x3,-x4+1/2
29 -x1+1/2,-x2+1/2,-x3,-x4
30 x1+1/2,x2+1/2,-x3,-x4+1/2
31 x1+1/2,-x2+1/2,x3,x4
32 -x1+1/2,x2+1/2,x3,x4+1/2

a: 6.1991(3) Å [ Help ]

b: 6.1987(4) Å [ Help ]

c: 11.1488(4) Å [ Help ]

α: 90 ° [ Help ]

β: 90 ° [ Help ]

γ: 90 ° [ Help ]

Volume: 428.41(4) Å3 [ Help ]

Modulation dimension: 1 [ Help ]

Measured independent wave vectors: [ Help ]

Wave vector id q_x q_y q_z
1 0.000000 0.000000 0.174100

Z: 4 [ Help ]

Cell determination reflection Nb.: 1000 [ Help ]

θ(min) for cell determination: 1.5 ° [ Help ]

θ(max) for cell determination: 22 ° [ Help ]

Cell measurement temperature: 20 K [ Help ]

μ: 5.91 mm-1 [ Help ]

Absorption correction type: empirical [ Help ]

Absorption correction remarks: SADABS, Program for Empirical Absorption Correction of Area Detector Data, G. M. Sheldrick, 1996 [ Help ]

Minimum transmission factor: 0.3192 [ Help ]

Maximum transmission factor: 0.3676 [ Help ]

Refinement details


Refinement remarks: ? [ Help ]

Total nb. of reflections: 498 [ Help ]

Nb. of observed reflections: 439 [ Help ]

Intense reflections threshold: I>3σ(I) [ Help ]

Refinement based on: F [ Help ]

R(obs): 0.0242 [ Help ]

wR(obs): 0.0248 [ Help ]

R(all): 0.0255 [ Help ]

wR(all): 0.0250 [ Help ]

S(all): 0.88 [ Help ]

S(obs): 0.93 [ Help ]

Nb. of reflections: 498 [ Help ]

Nb. of parameters: 18 [ Help ]

Number of restraints: 0 [ Help ]

Number of constraints: 0 [ Help ]

Weighting scheme: sigma [ Help ]

Weighting scheme remarks: w=1/(σ2(F)+0.0001F2) [ Help ]

Δ/σ(max): 0.0000 [ Help ]

Δ/σ(mean): 0.0000 [ Help ]

Δρ(max): 1.58 e_Å-3 [ Help ]

Δρ(min): -1.49 e_Å-3 [ Help ]

Extinction method: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974) [ Help ]

Extinction coefficient: 130(30) [ Help ]

Structural Information


Average Structure: [ Help ]

Atom site label Atom symbol x y z ADP type Uiso/equiv Symmetry multiplicity Occupancy Coords from (d)iffraction or (c)alculated Coords restraints or constraints Disordered cluster Disordered group
Eu1 Eu 0 0 0 Uani 0.0061(2) 4 1 d . . .
Al1 Al 0.25 0.25 0.25 Uani 0.0074(10) 8 1 d . . .
Al2 Al 0 0 0.38495(13) Uani 0.0061(8) 8 1 d . . .

ADP components: [ Help ]

Atom site label Atom site symbol U11 U22 U33 U12 U13 U23
Eu1 Eu 0.0000(4) 0.0124(5) 0.00587(17) 0 0 0
Al1 Al 0.0038(17) 0.011(2) 0.0074(6) 0 0 0
Al2 Al 0.0016(15) 0.011(2) 0.0058(6) 0 0 0

Fourier Wave Vectors (explicit: q_x,q_y,q_z or coefficients: q_1,q_2,...): [ Help ]

Wave vector code q_1
1 1

Definition of the displacive (translational) Fourier series: [ Help ]

Modulation code Atom site label Displacement axis Wave vector code
Eu1x1 Eu1 x 1
Eu1y1 Eu1 y 1
Eu1z1 Eu1 z 1
Al1x1 Al1 x 1
Al1y1 Al1 y 1
Al1z1 Al1 z 1
Al2x1 Al2 x 1
Al2y1 Al2 y 1
Al2z1 Al2 z 1

Displacive (translational) Fourier coefficients: [ Help ]

Modulation code Cosine coefficient Sine coefficient
Eu1x1 0 -0.02349(10)
Eu1y1 0 0
Eu1z1 0 0
Al1x1 0 -0.0225(4)
Al1y1 -0.0118(5) 0
Al1z1 0 0
Al2x1 -0.0108(4) -0.0242(4)
Al2y1 0 0
Al2z1 0 0

III

Chemical data


Common Name: EuAl4 [ Help ]

Structural Formula Sum: Al4 Eu1 [ Help ]

Formula weight: 259.9 Da [ Help ]

Crystallographic data and experimental details


Crystal system: orthorhombic [ Help ]

Superspace group name: Fmmm(00γ)s00 [ Help ]

Symmetry operations of the superspace group: [ Help ]

Operation code Operation in algebraic form
1 x1,x2,x3,x4
2 -x1,-x2,x3,x4+1/2
3 -x1,x2,-x3,-x4
4 x1,-x2,-x3,-x4+1/2
5 -x1,-x2,-x3,-x4
6 x1,x2,-x3,-x4+1/2
7 x1,-x2,x3,x4
8 -x1,x2,x3,x4+1/2
9 x1,x2+1/2,x3+1/2,x4
10 -x1,-x2+1/2,x3+1/2,x4+1/2
11 -x1,x2+1/2,-x3+1/2,-x4
12 x1,-x2+1/2,-x3+1/2,-x4+1/2
13 -x1,-x2+1/2,-x3+1/2,-x4
14 x1,x2+1/2,-x3+1/2,-x4+1/2
15 x1,-x2+1/2,x3+1/2,x4
16 -x1,x2+1/2,x3+1/2,x4+1/2
17 x1+1/2,x2,x3+1/2,x4
18 -x1+1/2,-x2,x3+1/2,x4+1/2
19 -x1+1/2,x2,-x3+1/2,-x4
20 x1+1/2,-x2,-x3+1/2,-x4+1/2
21 -x1+1/2,-x2,-x3+1/2,-x4
22 x1+1/2,x2,-x3+1/2,-x4+1/2
23 x1+1/2,-x2,x3+1/2,x4
24 -x1+1/2,x2,x3+1/2,x4+1/2
25 x1+1/2,x2+1/2,x3,x4
26 -x1+1/2,-x2+1/2,x3,x4+1/2
27 -x1+1/2,x2+1/2,-x3,-x4
28 x1+1/2,-x2+1/2,-x3,-x4+1/2
29 -x1+1/2,-x2+1/2,-x3,-x4
30 x1+1/2,x2+1/2,-x3,-x4+1/2
31 x1+1/2,-x2+1/2,x3,x4
32 -x1+1/2,x2+1/2,x3,x4+1/2

a: 6.1992(4) Å [ Help ]

b: 6.2001(4) Å [ Help ]

c: 11.1477(3) Å [ Help ]

α: 90 ° [ Help ]

β: 90 ° [ Help ]

γ: 90 ° [ Help ]

Volume: 428.47(4) Å3 [ Help ]

Modulation dimension: 1 [ Help ]

Measured independent wave vectors: [ Help ]

Wave vector id q_x q_y q_z
1 0.000000 0.000000 0.178100

Z: 4 [ Help ]

Cell determination reflection Nb.: 1000 [ Help ]

θ(min) for cell determination: 1.5 ° [ Help ]

θ(max) for cell determination: 22 ° [ Help ]

Cell measurement temperature: 70 K [ Help ]

μ: 5.909 mm-1 [ Help ]

Absorption correction type: empirical [ Help ]

Absorption correction remarks: SADABS, Program for Empirical Absorption Correction of Area Detector Data, G. M. Sheldrick, 1996 [ Help ]

Minimum transmission factor: 0.3209 [ Help ]

Maximum transmission factor: 0.3732 [ Help ]

Refinement details


Total nb. of reflections: 490 [ Help ]

Nb. of observed reflections: 453 [ Help ]

Intense reflections threshold: I>3σ(I) [ Help ]

Refinement based on: F [ Help ]

R(obs): 0.0220 [ Help ]

wR(obs): 0.0242 [ Help ]

R(all): 0.0232 [ Help ]

wR(all): 0.0245 [ Help ]

S(all): 1.09 [ Help ]

S(obs): 1.13 [ Help ]

Nb. of reflections: 490 [ Help ]

Nb. of parameters: 18 [ Help ]

Number of restraints: 0 [ Help ]

Number of constraints: 0 [ Help ]

Weighting scheme: sigma [ Help ]

Weighting scheme remarks: w=1/(σ2(F)+0.0001F2) [ Help ]

Δ/σ(max): 0.0001 [ Help ]

Δ/σ(mean): 0.0000 [ Help ]

Δρ(max): 3.58 e_Å-3 [ Help ]

Δρ(min): -2.40 e_Å-3 [ Help ]

Extinction method: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974) [ Help ]

Extinction coefficient: 55(10) [ Help ]

Structural Information


Average Structure: [ Help ]

Atom site label Atom symbol x y z ADP type Uiso/equiv Symmetry multiplicity Occupancy Coords from (d)iffraction or (c)alculated Coords restraints or constraints Disordered cluster Disordered group
Eu1 Eu 0 0 0 Uani 0.0083(2) 4 2 d . . .
Al1 Al 0.25 0.25 0.25 Uani 0.0080(9) 8 2 d . . .
Al2 Al 0 0 0.38491(12) Uani 0.0077(8) 8 2 d . . .

ADP components: [ Help ]

Atom site label Atom site symbol U11 U22 U33 U12 U13 U23
Eu1 Eu 0.0011(3) 0.0157(5) 0.00813(16) 0 0 0
Al1 Al 0.0080(16) 0.008(2) 0.0079(5) 0 0 0
Al2 Al 0.0034(14) 0.0127(19) 0.0069(6) 0 0 0

Fourier Wave Vectors (explicit: q_x,q_y,q_z or coefficients: q_1,q_2,...): [ Help ]

Wave vector code q_1
1 1

Definition of the displacive (translational) Fourier series: [ Help ]

Modulation code Atom site label Displacement axis Wave vector code
Eu1x1 Eu1 x 1
Eu1y1 Eu1 y 1
Eu1z1 Eu1 z 1
Al1x1 Al1 x 1
Al1y1 Al1 y 1
Al1z1 Al1 z 1
Al2x1 Al2 x 1
Al2y1 Al2 y 1
Al2z1 Al2 z 1

Displacive (translational) Fourier coefficients: [ Help ]

Modulation code Cosine coefficient Sine coefficient
Eu1x1 0 -0.01977(8)
Eu1y1 0 0
Eu1z1 0 0
Al1x1 0 -0.0199(4)
Al1y1 -0.0100(4) 0
Al1z1 0 0
Al2x1 -0.0093(3) -0.0206(3)
Al2y1 0 0
Al2z1 0 0