Superconductivity and crystal structure of lithium under high pressure

Matsuoka, Toshifumi; Onoda, Suzue; Kaneshige, Masahiro; Nakamoto, Yuki; Shimizu, Katsuya; Kagayama, Tomoko; Ohishi, Yasuo

doi:10.1088/1742-6596/121/5/052003

Cited by 20 publications

(15 citation statements)

References 11 publications

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“…Further pressure increases beyond 30 GPa lead to structural transitions which lower T c . 9 Additionally it was recently shown that at around 70 GPa, Li undergoes a metal-to-insulator transition 10 while resistivity increases with pressure have also been observed for shock-wave experiments. 11 Previous theoretical studies indicate that the electronphonon coupling strength in lithium is substantial.…”

Section: Introductionmentioning

confidence: 83%

Superconductivity and electron-phonon coupling in lithium at high pressures

2010

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Using a first-principles pseudopotential approach we study the origin of superconductivity in lithium under pressure. A recently developed Wannier interpolation based technique that allows for ultradense sampling of electron-phonon parameters throughout the Brillouin zone was employed. The electron-phonon coupling strength as a function of pressure was calculated, precisely resolving many of the fine features of its distribution. The contributions to coupling arising from the Fermi surface topology, phonon dispersions, and electronphonon matrix elements were separately analyzed. It is found that of the constituent components, the electronphonon matrix elements are the most sensitive to pressure changes, and a particular phonon is responsible for high values of coupling. Additionally, the distribution of matrix elements over the Fermi surface is seen to be non-uniform and possesses a two-peak structure. Analysis of the Eliashberg spectral function ␣ 2 F͑͒ shows a considerable increase in spectral weight in the low-frequency region with the application of pressure. We estimate the superconducting transition temperature and find that the obtained values are in good accord with experiment.

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Section: Introductionmentioning

confidence: 83%

Superconductivity and electron-phonon coupling in lithium at high pressures

2010

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“…I meas ͑I cal ͒ is measured ͑calculated͒ relative intensity. ͑J.S.S.͒ 23 and the other ͑type 2͒ brought by another author ͑T.M.͒ from Osaka University 24. Both DACs utilize a He-loaded double diaphragm which allows one to change pressure at nearly any temperature below ambient.…”

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confidence: 99%

Superconductivity under high pressure in the binary compoundCaLi2

et al. 2008

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“…[14] natural Li Ref. [5] fcc 6 Li-µ*=0.17 ME (our work) cI16 6 Li-µ*=0.17 ME (our work) fcc 7 Li-µ*=0.17 ME (our work) fects should not be isotope dependent and, due to the harmonic scaling of phonon frequencies, we do not expect vertex corrections to yield any anomalous isotope effect either. Therefore, we discard hypothesis (i).…”

Section: Resultsmentioning

confidence: 61%

“…The lightest metal on the periodic table shows a nearly free-electron bcc structure at ambient conditions 2 . Although it could be expected to evolve to an even more free-electron like system with increasing pressure, it has been shown that pressure not only induces several structural transformations [3][4][5][6][7] , but also gives rise to a plethora of fascinating physical properties 8 . For instance, lithium becomes a semiconductor near 80 GPa 9 , it shows a maximum in the melting line 10 and melts below ambient temperature (190 K) at around 50 GPa 3 .…”

Section: Introductionmentioning

confidence: 99%

Anharmonicity and the isotope effect in superconducting lithium at high pressures: A first-principles approach

et al. 2017

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Recent experiments1 have shown that lithium presents an extremely anomalous isotope effect in the 15-25 GPa pressure range. In this article we have calculated the anharmonic phonon dispersion of 7 Li and 6 Li under pressure, their superconducting transition temperatures, and the associated isotope effect. We have found a huge anharmonic renormalization of a transverse acoustic soft mode along ΓK in the fcc phase, the expected structure at the pressure range of interest. In fact, the anharmonic correction dynamically stabilizes the fcc phase above 25 GPa. However, we have not found any anomalous scaling of the superconducting temperature with the isotopic mass. Additionally, we have also analyzed whether the two lithium isotopes adopting different structures could explain the observed anomalous behavior. According to our enthalpy calculations including zero-point motion and anharmonicity it would not be possible in a stable regime.

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Superconductivity and crystal structure of lithium under high pressure

Cited by 20 publications

References 11 publications

Superconductivity and electron-phonon coupling in lithium at high pressures

Superconductivity and electron-phonon coupling in lithium at high pressures

Superconductivity under high pressure in the binary compoundCaLi2

Anharmonicity and the isotope effect in superconducting lithium at high pressures: A first-principles approach

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