Least-squares Refinement of the Structure of RhSi (FeSi-type).

Engström, Ingvar; Johnsson, Torsten; Skansen, Terje; Brünvoll, J.; Hinton, Merv

doi:10.3891/acta.chem.scand.19-1508

Cited by 16 publications

(10 citation statements)

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“…We have identified several materials candidates in SG 198 that satisfy the above conditions for experimental viability. In the main text, we highlight RhSi [37], which we found in our materials search to be the strongest candidate for observing large Fermi arcs and bulk photogalvanic effects (SM D). There are also several other promising materials candidates isostructural to RhSi, which include CoSi [56], CoGe [58], RhGe [59], AlPd [60], AlPt [61], GaPd [63], and GaPt [64].…”

Section: Sm a Density Functional Theoretic Methodsmentioning

confidence: 89%

Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi

et al. 2017

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The theoretical proposal of chiral fermions in topological semimetals has led to a significant effort towards their experimental realization. In particular, the Fermi surfaces of chiral semimetals carry quantized Chern numbers, making them an attractive platform for the observation of exotic transport and optical phenomena. While the simplest example of a chiral fermion in condensed matter is a conventional |C|=1 Weyl fermion, recent theoretical works have proposed a number of unconventional chiral fermions beyond the standard model which are protected by unique combinations of topology and crystalline symmetries. However, materials candidates for experimentally probing the transport and response signatures of these unconventional fermions have thus far remained elusive. In this Letter, we propose the RhSi family in space group No. 198 as the ideal platform for the experimental examination of unconventional chiral fermions. We find that RhSi is a filling-enforced semimetal that features near its Fermi surface a chiral double sixfold-degenerate spin-1 Weyl node at R and a previously uncharacterized fourfold-degenerate chiral fermion at Γ. Each unconventional fermion displays Chern number ±4 at the Fermi level. We also show that RhSi displays the largest possible momentum separation of compensative chiral fermions, the largest proposed topologically nontrivial energy window, and the longest possible Fermi arcs on its surface. We conclude by proposing signatures of an exotic bulk photogalvanic response in RhSi.

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Section: Sm a Density Functional Theoretic Methodsmentioning

confidence: 89%

Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi

et al. 2017

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“…As evident, the calculated lattice constants and internal in-plane parameters are in good agreement and are within 1e2% of reported experimental values. On the other hand, c-RhSi crystallizes in the primitive cubic structure in FeSi-type lattice and belongs to P2 1 3 space group [21,30,31]. The structure, also referred to as a B20 structure, can be thought as a pair distorted face-centered-cubic structure with Fe and Si atoms displaced along the <111> direction.…”

Section: Crystal and Electronic Structurementioning

confidence: 99%

“…Like orthorhombic phase of RhSi, there are four symmetry-equivalent Rh and two symmetry equivalent Si atoms per primitive cubic cell. There are two internal in-plane parameters, u Si , u Rh for Si and Rh atoms [31]. The unit cell of c-RhSi is shown in Fig.…”

Section: Crystal and Electronic Structurementioning

confidence: 99%

First principles study of structural, electronic and elastic properties of cubic and orthorhombic RhSi

Niranjan

2012

Intermetallics

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“…We have employed the generalized gradient approximations within the Perdew-Burke-Ernzerhof scheme [55] as an exchangecorrelation functional. The lattice parameters of the chiral cubic crystal RhSi have been chosen based on experimental measurements [56,57]. Four atoms of Rh and four atoms of Si in the unit cell are located in the Wyck- off positions for the space group P 2 1 3 [27,56].…”

mentioning

confidence: 99%

“…The lattice parameters of the chiral cubic crystal RhSi have been chosen based on experimental measurements [56,57]. Four atoms of Rh and four atoms of Si in the unit cell are located in the Wyck- off positions for the space group P 2 1 3 [27,56]. We have performed our calculations on a 40 × 40 × 40 k-point grid.…”

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confidence: 99%

Suppression of second-harmonic generation from linear bands in the topological multifold semimetal RhSi

Lu,

Sayyad,

Sánchez-MartÍnez

et al. 2021

Preprint

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Recent experiments in the topological Weyl semimetal TaAs have observed record-breaking second-harmonic generation, a non-linear optical response at 2ω generated by an incoming light source at ω. However, whether second-harmonic generation is enhanced in topological semimetals in general is a challenging open question because their band structure entangles the contributions arising from trivial bands and topological band crossings. In this work, we circumvent this problem by studying RhSi, a chiral topological semimetal with a simple band structure with topological multifold fermions close to the Fermi energy. We measure second-harmonic generation (SHG) in a wide frequency window, ω ∈ [0.27, 1.5] eV and, using first principle calculations, we establish that, due to their linear dispersion, the contribution of multifold fermions to SHG is subdominant as compared with other regions in the Brillouin zone. Our calculations suggest that parts of the bands where the dispersion is relatively flat contribute significantly to SHG. As a whole, our results suggest avenues to enhance SHG responses.

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Least-squares Refinement of the Structure of RhSi (FeSi-type).

Cited by 16 publications

References 0 publications

Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi

Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi

First principles study of structural, electronic and elastic properties of cubic and orthorhombic RhSi

Suppression of second-harmonic generation from linear bands in the topological multifold semimetal RhSi

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