Superconducting ground state of the nonsymmorphic superconducting compound 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Zr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mi>Ir</mml:mi></mml:mrow></mml:math>

Mandal, Manasi; Patra, Chandan; Kataria, Anshu; Singh, Deepak; Biswas⃰, Pabitra Kumar; Lord, J. S.; Hillier, A. D.; Singh, R. P.

doi:10.1103/physrevb.104.054509

Cited by 9 publications

(10 citation statements)

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“…The strength of the attractive interaction between the electron and phonon can be estimated by the electron-phonon coupling constant λ e-ph in the McMillan equation [52] 04 , where μ * (= 0.13 for many intermetallic superconductors) is the repulsive screened Coulomb parameter. The calculated value of λ e-ph = 0.67 represents Re 2 Hf as a moderately coupled superconductor [53,54].…”

Section: C2mentioning

confidence: 93%

Time-reversal symmetry breaking in frustrated superconductor Re2Hf

et al. 2022

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Geometrical frustration leads to novel quantum phenomena such as the spin-liquid phase in triangular and kagome lattices. Intraband and interband Fermi surface (FS) nesting can drive unique superconducting (SC) ground states with d-wave and s ± -pairing symmetries, respectively, according to the criterion that the SC gap changes sign across the nesting wave vector. For an odd number of FSs, when multiple interband nesting is of comparable strength, the sign-reversal criterion between different FS sheets can lead to frustration, which promotes novel SC order parameters. Here, we report the experimental observation of a time-reversal symmetry breaking pairing state in Re 2 Hf resulting from FS nesting frustration. Furthermore, our electronic specific heat and transverse-field muon spin rotation experiments suggest a fully gapped pairing symmetry. The first-principles electronic structure calculation reveals multiple Fermi surface sheets with comparable interband nesting strength. Implementing the ab initio band structure, we compute spin-fluctuation mediated SC pairing symmetry which reveals an s + is -pairing state-consistent with experimental observations. Our investigation demonstrates an alternative SC state which provides a putative setting for both applied and fundamental study.

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Section: C2mentioning

confidence: 93%

Time-reversal symmetry breaking in frustrated superconductor Re2Hf

et al. 2022

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“…It is interesting to note that Mandal et al [ 87 ] defined

as by

(and for this definition, the derived

) as well as by the

criterion (and for this definition, the derived

) for bulk Zr 2 Ir single crystals. This result demonstrates that

defined by the

criterion can be overestimated by a factor of 1.4.…”

Section: The Upper Critical Field Definitionmentioning

confidence: 99%

“…Returning now to the definition of the upper critical field, we can note that in several studies performed on perfect single-phase superconductors, the diamagnetic response was detected at

which is below (and in many cases is well below) the temperature at which the resistance drops to zero; that is,

[ 35 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 ]. These rare but high-quality experimental reports provide additional evidence for the need to define the

by at least the

criterion, which is the most accurate experimental value for the superconducting state collapse/emergence if only resistive measurements have been performed for the given sample.…”

Section: The Upper Critical Field Definitionmentioning

confidence: 99%

“…These rare but high-quality experimental reports provide additional evidence for the need to define the

by at least the

criterion, which is the most accurate experimental value for the superconducting state collapse/emergence if only resistive measurements have been performed for the given sample. This

definition has been implemented, but, again, in very rare studies [ 82 , 87 , 91 , 92 , 93 ] in comparison with the majority of studies, where

was defined by the

criterion (see, for instance, [ 94 , 95 ]).…”

Section: The Upper Critical Field Definitionmentioning

confidence: 99%

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Intrinsic Coherence Length Anisotropy in Nickelates and Some Iron-Based Superconductors

Talantsev

2023

Materials

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Nickelate superconductors, R1−xAxNiO2 (where R is a rare earth metal and A = Sr, Ca), experimentally discovered in 2019, exhibit many unexplained mysteries, such as the existence of a superconducting state with Tc (up to 18 K) in thin films and yet absent in bulk materials. Another unexplained mystery of nickelates is their temperature-dependent upper critical field, Bc2(T), which can be nicely fitted to two-dimensional (2D) models; however, the deduced film thickness, dsc,GL, exceeds the physical film thickness, dsc, by a manifold. To address the latter, it should be noted that 2D models assume that dsc is less than the in-plane and out-of-plane ground-state coherence lengths, dsc<ξab(0) and dsc<ξc(0), respectively, and, in addition, that the inequality ξc(0)<ξab(0) satisfies. Analysis of the reported experimental Bc2(T) data showed that at least one of these conditions does not satisfy for R1-xAxNiO2 films. This implies that nickelate films are not 2D superconductors, despite the superconducting state being observed only in thin films. Based on this, here we propose an analytical three-dimensional (3D) model for a global data fit of in-plane and out-of-plane Bc2(T) in nickelates. The model is based on a heuristic expression for temperature-dependent coherence length anisotropy: γξ(T)=γξ(0)1−1a×TTc, where a>1 is a unitless free-fitting parameter. The proposed expression for γξ(T), perhaps, has a much broader application because it has been successfully applied to bulk pnictide and chalcogenide superconductors.

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“…Свойства сплавов А15 обусловлены их кристаллической структурой, а наличие высокотемпературной сверхпроводимости связано со структурной неустойчивостью. При этом электронная зонная структура соединений с фазами типа А15 отражает квазиодномерную природу цепочек из атомов сорта А. Изучение электронных свойств соединений типа Ti 3 Sb, Ti 3 Ir [2], Ta 3 Sb, Ta 3 Pb и Ta 3 Sn [3] с кубической сингонией (фаза A15, прототип Cr 3 Si) указывает на наличие сверхпроводимости в них. Зонная структура соединений типа A15 со спин-орбитальной связью характеризуется энергетической щелью вблизи уровня Ферми.…”

Section: Introductionunclassified

Ab initio расчет зонной структуры и свойств модификаций соединения Ti-=SUB=-3-=/SUB=-Sb, допированного литием

Asadov

Маммадова

Guseinova

et al. 2022

Физика Твердого Тела

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Using the density functional theory (DFT) in the local electron spin density approximation (LSDA), 2×2×2 supercells based on the Ti3Sb compound have been studied. The supercells contained their own vacancies and doped lithium atoms replacing Ti and/or Sb. The DFT-LSDA method was used to calculate the structural, electronic, and magnetic properties, the enthalpy of formation, and the cohesion energy of supercells of two modifications of the Ti3Sb compound. We studied supercells with cubic system (A15 type structure; a = 5.217 Å) and tetragonal system (D8_m type structure; а = 10.457 Å, с = 5.258 Å). It has been established that the distribution of the density of states of the Ti3Sb cubic system has a more metallic character than for the D8_mTi3Sb modification. The enhancement of "metallicity" in the cubic modification A15 Ti3Sb is associated with an increase in the Ti–Sb interatomic distance in the crystal. Due to this, the degree of metallic bonding increases during the electronic interaction between Ti and Sb atoms near the Fermi level in Ti3Sb. In DFT calculations, the spin-polarized density of states was taken into account. It has been established that in both modifications (A15 and D8_m) of Ti3Sb near the Fermi level for s, p, d-states with spin "up" and spin "down" there is a spin imbalance in the population of energy levels. Defect-containing supercells based on Ti3Sb were studied by DFT-LSDA calculations. It is shown that Ti and/or Sb vacancies in the lattices of Ti3Sb crystals of both modifications (A15 and D8_m) increase the magnetic moment (M) as compared to the value of M (M_tot = 0.08 μ_B) of a “pure” Ti3Sb crystal. Considering that Al5 Ti3Sb is also interesting as a material for Li-ion batteries, we studied Ti3Sb–Li supercells doped with lithium. Li-doping and the creation of own Ti and/or Sb vacancies changes the distance between atoms in Ti3Sb. Correspondingly, the resulting local magnetic moments near the Ti or Sb vacancies also change. The enthalpy of formation and magnetic moment of Ti3Sb and Ti3Sb–Li based supercells are calculated. DFT calculations of the structural stability of binary compounds (phases) have been carried out, and the stability of conodes between phases in the Ti–Sb–Li system has been established. The isothermal section of the Ti–Sb–Li system was plotted at 298 K. It is shown that the introduction of various lithium concentrations (<6.25 at. % Li) into the Ti3Sb (Space group Pm3 ̅n; № 223; a = 5.217 Å) crystal lattice reduces the partial magnetic moment of Ti in the Ti3Sb–Li supercell.

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Superconducting ground state of the nonsymmorphic superconducting compound Zr2Ir

Cited by 9 publications

References 46 publications

Time-reversal symmetry breaking in frustrated superconductor Re2Hf

Time-reversal symmetry breaking in frustrated superconductor Re2Hf

Intrinsic Coherence Length Anisotropy in Nickelates and Some Iron-Based Superconductors

Ab initio расчет зонной структуры и свойств модификаций соединения Ti-=SUB=-3-=/SUB=-Sb, допированного литием

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