Soft-Mode Behavior in Ternary Silicides MAlSi (M=Ca, Sr, Ba)

Heid, R.; Bohnen, K.‐P.; Renker, B.; Adelmann, P.; Wolf, Th.; Ernst, Damien; Schober, H.

doi:10.1007/s10909-007-9325-x

Cited by 17 publications

(24 citation statements)

References 30 publications

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“…The existence of an ultrasoft phonon mode was suggested by Mazin and Papaconstantopoulos [10] to reconcile their calculated results with available experimental data. Such an assumption has been confirmed by our previous calculations [11][12][13] using the full-potential linear response LMTO method and the pseudopotential calculations by Giantomassi et al [14] and Heid et al [15]. In those works the soft mode plays an important role in superconductivity for CaAlSi.…”

Section: Introductionsupporting

confidence: 59%

“…Experimental [2][3][4][5][6][7][8] and theoretical [9][10][11][12][13][14][15][16] investigations have been made for understanding the nature for these compounds. Magnetic and transport measurements indicated that these materials are type II superconductors and the charge carriers are mainly electron-like, in contrast to hole carriers in MgB 2 .…”

Section: Introductionmentioning

confidence: 99%

“…Very interestingly, Lue et al [18] presented a clear NMR evidence for the coexistence of different double crystal structures (disordered and ordered) in CaAlSi. For CaAlSi and SrAlSi, using the ordered 1H-like model, the electronic structures, and electron-phonon (EP) interactions have been studied from the first-principles calculations [9][10][11][12][13][14][15][16]. From the LDA calculations, Mazin and Papaconstantopoulos [10] suggested that the 1H structure is the ground state for CaAlSi and SrAlSi compounds.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of structure on the superconductivity of CaAlSi and SrAlSi: Density functional calculations

Huang¹,

Wang²,

Shu³

et al. 2008

Physica C: Superconductivity

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Section: Introductionsupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of structure on the superconductivity of CaAlSi and SrAlSi: Density functional calculations

Huang¹,

Wang²,

Shu³

et al. 2008

Physica C: Superconductivity

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“…13,14 The interplay of these two ingredients gives rise to intriguing effects both on the normal and the superconducting properties. The presence of an ultrasoft phonon mode at ∼7 meV was initially evidenced by first-principles calculations 11,12,15,16,17 and recently confirmed by neutron-scattering experiments. 17 The ultrasoft phonon modes are believed to induce strong eph coupling and to lead to an enhanced specific heat anomaly at T c as well as to a positive pressure dependence of T c in CaAlSi.…”

mentioning

confidence: 70%

“…The presence of an ultrasoft phonon mode at ∼7 meV was initially evidenced by first-principles calculations 11,12,15,16,17 and recently confirmed by neutron-scattering experiments. 17 The ultrasoft phonon modes are believed to induce strong eph coupling and to lead to an enhanced specific heat anomaly at T c as well as to a positive pressure dependence of T c in CaAlSi. These effects have not been observed in the isoelectronic and isostructural SrAlSi which does not display any signature of soft phonon modes.…”

mentioning

confidence: 70%

Pressure effects on the superconducting transition innH-CaAlSi

et al. 2008

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We present a combined experimental and theoretical study of the effects of pressure on Tc of the hexagonal layered superconductors nH -CaAlSi (n = 1, 5, 6), where nH labels the different stacking variants that were recently discovered. Experimentally, the pressure dependence of Tc has been investigated by measuring the magnetic susceptibility of single crystals up to 10 kbar. In contrast to previous results on polycrystalline samples, single crystals with different stacking sequences display different pressure dependences of Tc. 1H-CaAlSi shows a decrease of Tc with pressure, whereas 5H and 6H-CaAlSi exhibit an increase of Tc with pressure. Ab-initio calculations for 1H, 5H and 6H -CaAlSi reveal that an ultrasoft phonon branch associated to out-of-plane vibrations of the Al-Si layers softens with pressure, leading to a structural instability at high pressures. For 1H-CaAlSi the softening is not sufficient to cause an increase of Tc, which is consistent with the present experiments, but adverse to previous reports. For 5H and 6H the softening provides the mechanism to understand the observed increase of Tc with pressure. Calculations for hypothetical 2H and 3H stacking variants reveal qualitative and quantitative differences.

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Thickness‐Dependent Superconductivity in a Layered Electride on Silicon

Averyanov

Sokolov

Parfenov

et al. 2023

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Layered materials exhibit a plethora of fascinating properties. The challenge is to make the materials into epitaxial films, preferably integrated with mature technological platforms to facilitate their potential applications. Progress in this direction can establish the film thickness as a valuable parameter to control various phenomena, superconductivity in particular. Here, a synthetic route to epitaxial films of SrAlSi, a layered superconducting electride, on silicon is designed. A set of films ranging in thickness is synthesized employing a silicene‐based template. Their structure and superconductivity are explored by a combination of techniques. Two regimes of TC dependence on the film thickness are identified, the coherence length being the crossover parameter. The results can be extended to syntheses of other honeycomb‐lattice ternary compounds on Si or Ge exhibiting superconducting, magnetic, and other properties.

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Soft-Mode Behavior in Ternary Silicides MAlSi (M=Ca, Sr, Ba)

Cited by 17 publications

References 30 publications

Effect of structure on the superconductivity of CaAlSi and SrAlSi: Density functional calculations

Effect of structure on the superconductivity of CaAlSi and SrAlSi: Density functional calculations

Pressure effects on the superconducting transition innH-CaAlSi

Thickness‐Dependent Superconductivity in a Layered Electride on Silicon

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