Effect of paramagnetic impurities on superconductivity in polyhydrides: s-wave order parameter in Nd-doped LaH10

Semenok, Dmitrii V.; Troyan, I. A.; Sadakov, A. V.; Zhou, Di; Galasso, Michele; Kvashnin, Alexander G.; Kruglov, Ivan A.; Быков, А. А.; Terent’ev, Konstantin Y.; Cherepahin, Alexander V.; Sobolevskiy, O. A.; Pervakov, K. S.; Seregin, Alexey Yu.; Helm, Toni; Förster, Tobias; Grockowiak, Audrey; Tozer, S. W.; Nakamoto, Yuki; Shimizu, Katsuya; Pudalov, V. M.; Lyubutin, I. S.; Oganov, Artem R.

doi:10.21203/rs.3.rs-1445631/v1

Cited by 8 publications

(18 citation statements)

References 60 publications

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“…Furthermore, no superconductivity or only lowtemperature superconductivity was observed in other similar RE metal superhydrides, where strongly correlated interactions of 4f electrons dramatically suppress the superconductivity 24,[48][49][50][51][52] . It has been reported that the superconductivity of LaH 10 was dramatically suppressed by doped Nd 53 (each atomic percent of Nd causes a decrease in T c of 10-11 K), which can be reasonably understood by the well-known impure superconductor theory proposed by Abrikosov and Gor'kov 37 . If half of the weakly magnetic Ce in CeH 9 is replaced by non-magnetic La, Abrikosov-Gor'kov suppression-like effect of Ce should be significantly weakened, resulting in the giant lift of T c in (La,Ce)H 9 over that in CeH 9 .…”

Section: Discussionmentioning

confidence: 81%

Giant enhancement of superconducting critical temperature in substitutional alloy (La,Ce)H9

Nakamoto

Shimizu

et al. 2022

Preprint

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A sharp focus of current research on superconducting superhydrides is to raise their critical temperature Tc at moderate pressures. Here, we report a striking discovery of giant enhancement of Tc in CeH9 obtained via random substitution of half Ce by La, leading to equal-atomic (La,Ce)H9 alloy stabilized by maximum configurational entropy, containing the LaH9 unit that is unstable in pure compound form. The synthesized (La,Ce)H9 alloy exhibits Tc of 148-178 K in the pressure range of 97-172 GPa, representing up to 80% enhancement of Tc compared to pure CeH9 and showcasing the highest Tc at sub-megabar pressure among the known superhydrides. This work demonstrates substitutional alloying as a highly effective enabling tool for substantially enhancing Tc via atypical compositional modulation inside suitably selected host crystal. This optimal substitutional alloying approach opens a promising avenue for synthesis of high-entropy multinary superhydrides that may exhibit further increased Tc at even lower pressures.

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Section: Discussionmentioning

confidence: 81%

Giant enhancement of superconducting critical temperature in substitutional alloy (La,Ce)H9

Nakamoto

Shimizu

et al. 2022

Preprint

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“…It is noteworthy to mention that partial replacement of La atoms by magnetic Nd atoms results in significant suppression of superconductivity in LaH 10 . [41] This provides a hint to design new superconducting materials. Among the ternary hydrides with cage structures, we note that some of their specific compositions such as (A,B)H 6 , (A,B)H 9 , and (A,B)H 10 can be obtained by mixing their parent compounds (AH x and BH x , x = 6, 9, and 10) with the same cage structures.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the superconductivity of ternary clathrate hydride has also attracted a lot of attention, and most of them cover the hydrides of alkaline-earth metals and rare-earth metals. [9,[31][32][33][34][35][36][37][38][39][40][41] Although the theoretically predicted T c of Li 2 MgH 16 composed of alkali and alkaline-earth metals at 250 GPa is 473 K, its enthalpy of formation lies above the convex hull [8,42] and its synthesis in experiment is still a great challenge. It is noteworthy to mention that partial replacement of La atoms by magnetic Nd atoms results in significant suppression of superconductivity in LaH 10 .…”

Section: Introductionmentioning

confidence: 99%

(La,Th)H$_{10}$: the potential high-$T_{c}$ superconductors stabilized thermodynamically below 200 GPa

Song¹,

Hou²,

Hongo³

2022

Preprint

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The recent high-pressure experimental discovery of superconductivity in (La,Y)H 10 , (La,Ce)H 9 , (La,Ce)H 10 , (Y,Ce)H 9 , and (La,Nd)H 10 shows that the ternary rare-earth clathrate hydride can be promising candidate for high-temperature superconductor. In this work, we theoretically demonstrate that the combination of actinidemetal thorium (Th) and rare-earth-metal lanthanum (La) with hydrogen can also form some ternary hydrides with cage-like structures to be stable at 200 GPa. Using the evolutionary algorithms combined with the firstprinciples calculations, we have predicted the pressure-dependent ternary phase diagram of La x Th y H z , particularly including the case of (La 1−x Th x )H n [or designated as (La,Th)H n for simplicity]. Our calculations show that the hydrogen-rich phases such as (La,Th)H 9 (only including P 6m2-LaThH 18 ) and (La,Th)H 10 (including I4/mmm-La 3 ThH 40 , R 3m-LaThH 20 , and I4/mmm-LaTh 3 H 40 ) with H 29 and H 32 cages can be thermodynamically stable below 200 GPa. However, the phase decomposition can happen to only (La,Th)H 9 when the pressure is above 150 GPa. More importantly, the electron-phonon coupling (EPC) calculations show that the (La,Th)H 10 series could the potential superconductors, of which I4/mmm-La 3 ThH 40 at 200 GPa exhibits the large EPC constant λ = 2.46 with a highest transition temperature (T c ) of 210 K. Since there are few previous studies on ternary hydrides composed of actinide metals, the present work would greatly stimulate the further discovery of this type of ternary hydrides and provide useful guidance for the high-pressure experimental studies on them.

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“…The attention has been to ternary systems, typically for La-based HTSC polyhydrides 21,22,23 . In contrast to rich theoretical studies, ternary hydrides have more research space in experiments 24,25 . However, they remained elusive because of uncontrollable and complex synthesis.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of superconducting properties in the La–Ce–H system at moderate pressures

Chen

Huang

Semenok³

et al. 2022

Preprint

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Compressed polyhydrides have been regarded as an important platform for exploring high-temperature superconductors. The disordered states with high entropy could possess better superconducting properties than conventional periodic structures. Here, we have discovered a new high entropy superconducting La–Ce polyhydride (initial ratio La: Ce = 2.5–3.5:1), which is stable under low pressures with the giant enhancement of superconducting properties compared with the binary La-H and Ce-H system. Its superconductivity at 176 K was strikingly preserved to about 100 GPa, and the extrapolated upper critical field Hc2(0) reached 235 T, both of which are the record values among the synthesized polyhydrides at 100 GPa. We also performed the contrast experiments on binary lanthanum hydride that show a much lower Tc (up to 100 K) at the same pressure range. The experimental results and theoretical calculation indicate the disordering state of the La-Ce-H system with high configurational entropy. The aroused configurational entropy shifts the La-Ce-H system towards a dirty limit that not only enhanced the stability but also improved the superconducting properties by softening the phonon frequency (ω), shorting the electron mean free path (ℓ), and increasing the electron-phonon coupling parameter (λe−p). These results show how better superconductors can be engineered in this new class of hydrides.

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Effect of paramagnetic impurities on superconductivity in polyhydrides: s-wave order parameter in Nd-doped LaH10

Cited by 8 publications

References 60 publications

Giant enhancement of superconducting critical temperature in substitutional alloy (La,Ce)H9

Giant enhancement of superconducting critical temperature in substitutional alloy (La,Ce)H9

(La,Th)H$_{10}$: the potential high-$T_{c}$ superconductors stabilized thermodynamically below 200 GPa

Enhancement of superconducting properties in the La–Ce–H system at moderate pressures

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