Discovery of a Weyl Fermion Semimetal and Topological Fermi Arcs
Science, 2015 · paper · Physics
Reports photoemission experiments on TaAs crystals that directly observe surface Fermi arcs and bulk Weyl cones and nodes. The authors present TaAs as the first discovered Weyl semimetal, with Fermi arcs ending on the Weyl nodes.
Checked: PDF from arxiv.org, fetched 4 Oct 2026. Page numbers are those of that PDF.
5 findings
Substance "a screw axis that sends the crystal back into itself after a C4 rotation and a translation by c/2 along the rotation axis" conflicts with the stated space group I4_1md (#109), whose 4_1 screw axis translates by c/4.
- p. 6 Surface electronic structure, first paragraph (inline formula c/2)
rotation and a translation by
- p. 4 Material system, space group (I4_1md, #109)
as consistently reported in previous structural studies
- p. 4 The material system, space group
(#109,
- p. 6 Surface electronic structure, first paragraph
a screw axis that sends the crystal back into itself after a C4 rotation and a translation by c/2 along the rotation axis
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: the Hermann-Mauguin symbol 4_1 denotes a fourfold rotation combined with a translation of one quarter of the lattice period (c/4). Page 4 image gives the space group as I4_1md (#109, C4v). Page 6 image shows the formula as C4 rotation plus translation c/2. My reworking: combining the 4_1 operation with the body-centring translation (1/2,1/2,1/2) gives 3c/4, and applying 4_1 twice gives C2 + c/2, so no fourfold operation of this group has a c/2 translation. The fraction is read from the image, not the text layer.
Second check: another model agreed
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Reference or label Text says the k_x and k_y planes are "shaded blue in Figs. 1, C and E", but Fig. 1C is an E-k band-structure plot with only a blue outlined box; blue-shaded planes appear only in Fig. 1E.
- p. 5 First paragraph
planes (shaded blue in Figs. 1, C and E)
- p. 15 Fig. 1 caption (C)
The blue box highlights the locations where bulk bands touch in the BZ.
- p. 15 Fig. 1 caption, panel C
The blue box highlights the locations where bulk bands touch in the BZ
Only the authors can say what is right here.
Judge's note: Page 5 image has the sentence as quoted. Page 15 image: panel C is a band structure along Γ-Σ-N-Σ1-Z-Γ-X with a blue rectangle near E=0, and the caption says "The blue box highlights the locations where bulk bands touch in the BZ". Panel E shows the blue-shaded mirror planes. The pointer to panel C for shaded planes does not match the figure; the authors probably meant the blue box, so they should say which.
Second check: another model agreed
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Reference or label Fig. 3 caption says Cut 1 "goes through two nearby W2 Weyl nodes along the k_y direction" and Fig. 3D is labelled k_y, but in Fig. 3C Cut 1 is drawn along the k_x axis direction, and the text places the nearby W2 pair at (±0.04, 0.53) Å^-1, i.e. split along k_x.
- p. 19 Fig. 3 caption (C) and panel D axis label
which goes through two nearby W2 Weyl nodes along the
- p. 10 Bulk-surface correspondence, W2 node coordinates
0.53
- p. 19 Fig. 3D horizontal axis
k_y (Å-1)
- p. 10 Bulk-surface correspondence, W2 node location
the W2 Weyl nodes to be at
Only the authors can say what is right here.
Judge's note: Page 19 image: in the calculated panel of Fig. 3C, the Cut 1 dotted line is horizontal through the node pair at the bottom of the map (near k_x=0, negative k_y), and the horizontal axis is k_x. The caption and the Fig. 3D axis both say k_y. Page 10 image gives the W2 nodes at (0.04±0.015, 0.53±0.015) Å^-1, so that pair is separated by 0.08 Å^-1 along the first (k_x) component. A symmetry-equivalent pair near the k_x axis would be split along k_y, so only the authors can say whether the label or the drawing is intended. Read at page resolution.
Second check: another model agreed
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Reference or label Fig. 4D (sharing its horizontal axis with 4C) has both axes labelled "k_y (Å-1)"; the horizontal axis (-0.1 to 0.1) should be k_x.
- p. 20 Fig. 4, panel D (and shared horizontal axis of panel C)
Weyl Fermion nodes
- p. 10 Bulk-surface correspondence, W2 node coordinates
0.53
Judge's note: Page 20 image: panels C and D have the vertical axis k_y (Å-1) from -0.4 to -0.6, and the horizontal axis under D, with ticks -0.1, 0.0, 0.1, is also labelled k_y (Å-1). Fig. 4E, whose dashed box is the zoom region, labels its horizontal axis k_x (Å-1), and the text on page 10 gives the positions as (0.04, 0.51) and (0.04, 0.53) Å^-1. The horizontal label in 4D is a mislabel. Read at page resolution.
Second check: another model agreed
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Reference or label Fig. 4D (page 20): the horizontal axis (-0.1 to 0.1) is labelled "k_y (Å-1)", the same as the vertical axis (-0.4 to -0.6, "k_y (Å-1)"); the horizontal axis should read k_x.
- p. 20 Fig. 4, panel D, horizontal axis label
k_y (Å-1)
- p. 10 Bulk-surface correspondence, W2 node location
the W2 Weyl nodes to be at
Judge's note: Viewed the page 20 image: panel D's vertical axis is k_y (-0.4 to -0.6) and the horizontal axis under panels C/D (-0.1, 0.0, 0.1) is also labelled k_y. The text on page 10 gives k_W2 = (0.04 ± 0.015, 0.53 ± 0.015) Å^-1, so the small coordinate is the first (k_x) component, and Fig. 4E's dotted box spans k_x about -0.15 to 0.15 with k_y -0.4 to -0.6. A map cannot have the same variable on both axes; this is a label slip with an evident fix.
Second check: another model agreed
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9 minor (typos and the like; most checked by the judge only)
Typo Missing space in "NoteAdded:" (should be "Note Added:").
- p. 1 Note added below the abstract
NoteAdded: This experimental discovery (Science 2015)
- p. 1 Note Added paragraph
NoteAdded:
Judge's note: Page 1 image shows "NoteAdded:" set as one word below the abstract; it is not an extraction artefact.
Second check: none (judge only)
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Typo Doubled full stop around the citation: "much experimental and theoretical work. (1-22)."
- p. 3 End of first paragraph
much experimental and theoretical work. (1-22).
Judge's note: Page 3 image shows a full stop after "work", then "(1-22)." with a second full stop. Elsewhere on the page citations sit before the full stop.
Second check: none (judge only)
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Typo Spelling "crystalizes in a body-centered tetragonal" (usual spelling: "crystallizes").
- p. 4 The material system and theoretical considerations, first sentence
crystalizes in a body-centered tetragonal
Judge's note: Page 4 image shows "crystalizes" with a single l. The single-l form is listed as a variant in some dictionaries, so this is a minor spelling point where either form could be defended.
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Typo Subject-verb disagreement: "those regions with positive spectral weight (blue) corresponds to the contour at" (should be "correspond").
- p. 7 First paragraph
(blue) corresponds to the contour at
Judge's note: Page 7 image shows "regions ... (red) correspond to" followed by "those regions ... (blue) corresponds to". Plural subject with singular verb.
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Typo Stray comma between subject and verb: "our SX-ARPES data alone, proves the existence".
- p. 9 last paragraph
our SX-ARPES data alone, proves the existence
Judge's note: Page 9 image, last paragraph, shows "Therefore, our SX-ARPES data alone, proves the existence of bulk Weyl nodes." The comma separates subject from verb.
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Typo Misplaced spacing around the comma: "In Figs. S5-7 ,we further show".
- p. 10 Bulk-surface correspondence, near end
In Figs. S5-7 ,we further show
Judge's note: Page 10 image shows a space before the comma and none after it. It is in the PDF, not an extraction artefact.
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Typo Reference 7: "R. Prasad, A Bansil" lacks the period after the initial "A".
- p. 11 Ref. 7
R. Prasad, A Bansil
Judge's note: Page 11 image, ref. 7, shows "A Bansil" with no period; every other initial in the entry has one.
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Typo Reference 30 gives the first author as "P. Perdew, K. Burke, M. Ernzerhof" (first initial apparently dropped; should be J. P. Perdew).
- p. 14 Reference 30
P. Perdew, K. Burke, M. Ernzerhof, Generalized Gradient Approximation Made Simple.
- p. 14 Ref. 30
P. Perdew, K. Burke, M. Ernzerhof
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: the first author of Phys. Rev. Lett. 77, 3865 (1996) is J. P. Perdew. Page 14 image confirms the entry reads "P. Perdew, K. Burke, M. Ernzerhof, Generalized Gradient Approximation Made Simple." The correct initials cannot be verified from the files.
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Typo Acknowledgments: "Gordon and Betty Moore Foundations EPiQS Initiative" lacks the possessive apostrophe ("Foundation's").
- p. 14 Acknowledgments
Gordon and Betty Moore Foundations EPiQS Initiative
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: the funder is a single body, the Gordon and Betty Moore Foundation. Page 14 image shows "Foundations EPiQS Initiative" with no apostrophe, while "Prime Minister's" on the next lines keeps its apostrophe, so this is not a rendering loss.
Second check: none (judge only)