Extremely strong coupling s-wave superconductivity in the medium-entropy alloy TiHfNbTa

Zeng, Lingyong; Hu, Xiaoming; Boubeche, Mebrouka; Li, Kuan; Li, Longfu; Yu, Peifeng; Wang, Kangwang; Zhang, Chao; Jin, Kui; Yao, Dao‐Xin; Luo, Huixia

doi:10.1007/s11433-023-2113-6

Cited by 7 publications

(4 citation statements)

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“…31 In addition, we fit the Pauli limiting field (μ 0 H P (T)) of TiVNbTa by the formula μ 0 H P (T) = 1.86T c . Table 1 summarizes the relevant superconducting parameters for TiVNbTa, TiHfNbTa, 18 and Ta 1/6 Nb 2/6 Hf 1/6 Zr 1/6 Ti 1/6 . 17 In addition, it can be seen that using the so-called α model, the traditional s-wave gap function can fit the data well and shows that the material is completely gapped.…”

Section: Resultsmentioning

confidence: 99%

“…Compared to conventional alloys, these multicomponent alloys show preeminent mechanical, thermal, physical, and chemical properties and robust superconductivity against disorder, − high pressure, , weak magnetic impurity, , and extremely strong s-wave coupling . Therefore, the preparation and investigation of HEA or MEA superconductors are still of scientific and technological interest.…”

Section: Introductionmentioning

confidence: 99%

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Superconductivity in the Medium-Entropy Alloy TiVNbTa with a Body-Centered Cubic Structure

Guo

et al. 2023

J. Phys. Chem. C

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Here, we report the TiVNbTa medium-entropy alloy (MEA) superconductor with the mixed 3d–5d elements synthesized by an arc-melting method. The TiVNbTa material has a body-centered cubic structure with the cell parameter a = 3.2547(3) Å. The superconducting properties of TiVNbTa were studied by resistivity, magnetic susceptibility, and specific heat measurements. The experimental results show that the bulk superconducting phase transition temperature of TiVNbTa is about 4.65 K, and the upper and lower critical fields are 49.3(4) mT and 5.9(5) T, respectively, which indicates that TiVNbTa is a type-II superconductor. First-principles calculations show that the d electrons of Ti, V, Nb, and Ta atoms play a significant role near the Fermi level. The results show that TiVNbTa is a traditional s-wave superconductor (ΔC el/γT c = 1.60(2), λep = 0.76(3)).

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Superconductivity in the Medium-Entropy Alloy TiVNbTa with a Body-Centered Cubic Structure

Guo

et al. 2023

J. Phys. Chem. C

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“…Furthermore, the estimation of the electron‐phonon coupling constant λ ep for TiHfNbTaMo HEA is derived from the Θ D value, employing the semiempirical McMillan formula

\ {\lambda }_{ep}{\mathrm{ = }}\frac{{{\mathrm{1}}{\mathrm{.04 + }}{{{\mu}}}^{\mathrm{*}}{\mathrm{ln}}( {\frac{{{\Theta }_D}}{{{\mathrm{1}}{\mathrm{.45}}{{\mathrm{T}}}_{\mathrm{c}}}}} )}}{{( {{\mathrm{1 - 0}}{\mathrm{.62}}{{{\mu}}}^{\mathrm{*}}} ){\mathrm{ln}}( {\frac{{{\Theta }_D}}{{{\mathrm{1}}{\mathrm{.45}}{{\mathrm{T}}}_{\mathrm{c}}}}} ){\mathrm{ - 1}}{\mathrm{.04}}}}\

. The Coulomb pseudopotential parameter µ * = 0.13, [ 44–46 ] is valid for intermetallic superconductors. Based on the T c and Θ D , we obtained λ ep = 0.60 for TiHfNbTaMo HEA, which allows us to classify the TiHfNbTaMo HEA as a superconductor exhibiting moderate electron–phonon coupling.…”

Section: Resultsmentioning

confidence: 99%

Superconductivity in the bcc‐Type High‐Entropy Alloy TiHfNbTaMo

Zeng,

Zhan,

Boubeche

et al. 2023

Adv Quantum Tech

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X‐ray powder diffraction, electrical resistivity, magnetization, and thermodynamic measurements are conducted to investigate the structure and superconducting properties of TiHfNbTaMo, a novel high‐entropy alloy possessing a valence electron count (VEC) of 4.8. The TiHfNbTaMo HEA is discovered to have a body‐centered cubic structure (space group ) with lattice parameters a = 3.445 (1) Å and a microscopically homogeneous distribution of the constituent elements. This material shows type‐II superconductivity with Tc = 3.42 K, lower critical field µ0Hc1(0) = 22.8 mT, and upper critical field µ0Hc2(0) = 3.95 T. Low‐temperature specific heat measurements show that the alloy is a conventional s‐wave type with a moderately coupled superconductor. First‐principles calculations show that the density of states (DOS) of the TiHfNbTaMo alloy is dominated by hybrid d orbitals of these five metal elements. Additionally, the TiHfNbTaMo HEA exhibits three van Hove singularities. Furthermore, the VEC and the composition of the elements (especially the Nb elemental content) affect the Tc of the bcc‐type HEA.

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“…1,2 Following the discovery of superconductivity in HEAs within the Ti-Zr-Hf-Nb-Ta alloy in 2014, 3 there has been a significant focus on investigating novel HEA superconductors. [4][5][6][7][8][9][10] Numerous intriguing superconducting properties have been documented, including the robustness of superconductivity under extreme pressure or magnetic fields and the cocktail effect in enhancing bulk superconductivity. [11][12][13][14] Furthermore, the superconducting transition temperature T c of HEAs superconductors is strongly related to the valence electron count (VEC) and composition.…”

Section: Introductionmentioning

confidence: 99%

Superconductivity and non-trivial band topology in high-entropy carbonitride Ti0.2Nb0.2Ta0.2Mo0.2W0.2C1-xNx

Zeng,

Hu,

Zhou

et al. 2023

TIMS

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High-entropy materials (HEMs) are widely recognized for their remarkable resistance to degradation and exceptional mechanical characteristics, rendering them valuable for use in challenging environments. Simultaneously, the investigation of novel attributes of HEMs has long been a crucial focus of scientific exploration. Based on this theoretical framework, we devised and produced a sequence of original bulk Ti0.2Nb0.2Ta0.2Mo0.2W0.2C1-xNx (0 �� x �� 0.45) superconductors. Furthermore, it has been observed that Ti0.2Nb0.2Ta0.2Mo0.2W0.2C1-xNx HECN ceramics possess type-�� Dirac points in the electronic band structure, implying that these unique bulk HECN ceramics have potential as candidates to bridge superconductivity with topology. These discoveries enhance our comprehension of the physical properties and potential applications of HECN ceramics, thereby establishing them as a promising platform for exploring unconventional physics, such as band topology and superconductivity.

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Extremely strong coupling s-wave superconductivity in the medium-entropy alloy TiHfNbTa

Cited by 7 publications

References 50 publications

Superconductivity in the Medium-Entropy Alloy TiVNbTa with a Body-Centered Cubic Structure

Superconductivity in the Medium-Entropy Alloy TiVNbTa with a Body-Centered Cubic Structure

Superconductivity in the bcc‐Type High‐Entropy Alloy TiHfNbTaMo

Superconductivity and non-trivial band topology in high-entropy carbonitride Ti<sub>0.2</sub>Nb<sub>0.2</sub>Ta<sub>0.2</sub>Mo<sub>0.2</sub>W<sub>0.2</sub>C<sub>1-<i>x</i></sub>N<sub><i>x</i></sub>

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