Possible superconductivity in Bismuth (111) bilayers. Their electronic and vibrational properties from first principles

Hinojosa‐Romero, David; Rodríguez, Isaías; Valladares, R.M.; Valladares, Ariel A.

doi:10.1557/adv.2018.119

Cited by 5 publications

(6 citation statements)

References 18 publications

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“…A year after our prediction, experimentalists proved us correct and they found that the Wyckoff structure superconducts below 0.53 mK at ambient pressure [9]. We had ventured to estimate superconducting temperatures for bismuth under various conditions; for the crystalline phase, that had not been found to superconduct, we succeeded; our other predictions await verification [7,10]. So, with this succinct background we decided that bismuth was the ideal "guinea pig" to test the effect of negative pressures and we undertook the search to see if it could become metallic or a semiconductor under expansion, and what the possibilities were to find it in a superconducting state.…”

Section: Introductionmentioning

confidence: 70%

Could Negative Pressures Turn Bismuth into a Metal? The Case of the Expanded

Quiroga¹,

Hinojosa‐Romero²,

Valladares³

et al. 2022

Preprint

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Materials may behave in non-expected ways when subject to unexpected conditions. For example, when Bi was turned into an amorphous phase (a-Bi) unexpectedly it became a superconductor at temperatures below 10 K. We provided an explanation as to why a-Bi superconducts and the crystalline (c-Bi) had not been found to do so: we computer calculated their electronic properties and found that a-Bi has a larger electron density of states, eDoS, at the Fermi surface than c-Bi and this explained the phenomenon. We even predicted an upper limit for the superconducting Tc of the crystalline phase, which was experimentally corroborated within the following year. We now decided to investigate what happens to crystalline (Wyckoff structure) and amorphous Bi when pressures below the atmospheric are applied (expansion). Here we show that when expanded, c-Bi becomes more metallic, since the eDoS increases when the volume increases for the Wyckoff structure, while the amorphous eDoS decreases. If the crystalline structure is maintained its Tc would rise under expansion, whereas it would diminish for the a-Bi. Expansion can be obtained in the laboratory by chemically etching Bi-based alloys, a process also known as dealloying, for example.

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Section: Introductionmentioning

confidence: 70%

Could Negative Pressures Turn Bismuth into a Metal? The Case of the Expanded

Quiroga¹,

Hinojosa‐Romero²,

Valladares³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Finally, the equations we shall use for the Γ phase are Tc Γ = {Tc W } 1/ η δ {1.13 θD W } ( η-1) / η , (5) where we have explicitly included the Wyckoff phase as the reference phase. Also, N(EF) Γ = η N(EF) W , (6) and…”

Section: The Methodsmentioning

confidence: 99%

“…However, it is possible to obtain results like the ones reported in this work that give an indication as to what materials may become superconductors if the N(E) and the F(ω) are known, and if the Cooper attraction sets in. In what follows we shall recur to some of our previous publications [3,[5][6][7] since the procedure is the same for these series of calculations.…”

Section: Procedure: the Bcs Approachmentioning

confidence: 99%

“…that we utilized in our previous work with good results [5][6][7]. F(ω) is the vDoS of the supercell under consideration, and ωmax is the maximum frequency of the corresponding vibrational spectrum.…”

Section: θD δ Exp (-1/ N(ef) δ V0)mentioning

confidence: 99%

“…A year later an experimental group corroborated that in fact Bi is a superconductor with a transition temperature of 0.5 mK, a result that eluded previous work 4 . Analogously we have studied low dimensional structures of bismuth, bilayers or bismuthene, and have predicted that they may become superconductive, with a transition temperature of T c L = 2.61 K, provided the Cooper pairing potential manifests itself in a similar manner as in the bulk 5,6 . Finally, since it is very suggestive that all phases of bismuth under pressure should superconduct we calculated N(E) and F(ω ) for Bi-IV and predicted a transition temperature of 4.25 K 7 , to be corroborated.…”

Section: Introductionmentioning

confidence: 99%

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A facile approach to calculating superconducting transition temperatures in the bismuth solid phases

Rodríguez

Hinojosa‐Romero

Valladares

et al. 2019

Sci Rep

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All solid phases of bismuth under pressure, but one, have been experimentally found to superconduct. From Bi-I to Bi-V, avoiding Bi-IV, they become superconductors and perhaps Bi-IV may also become superconductive. To investigate the influence of the electronic properties N(E ) and the vibrational properties F(ω) on their superconductivity we have ab initio calculated them for the corresponding experimental crystalline structures, and using a BCS approach have been able to determine their critical temperatures T c obtaining results close to experiment: For Bi-I (The Wyckoff Phase) we predicted a transition temperature of less than 1.3 mK and a year later a T c of 0.5 mK was measured; for Bi-II T c is 3.9 K measured and 3.6 K calculated; Bi-III has a measured T c of 7 K and 6.5 K calculated for the structure reported by Chen et al ., and for Bi-V T c ~ 8 K measured and 6.8 K calculated. Bi-IV has not been found to be a superconductor, but we have recently predicted a T c of 4.25 K.

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Superconductivity in Twisted Bismuth Bilayers

Rodríguez,

Valladares,

Hinojosa‐Romero

et al. 2024

Advanced Physics Research

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Two twisted bismuth bilayers, TBB, each with 120 atoms, are studied using their electron density of states and their vibrational density of states using first‐principles calculations. Metallic character at the Fermi level is found for the non‐rotated sample as well as for each sample rotated 0.5°, 1.0°, 1.5°, 2.0°, 2.5°, 3.0°, 4.0°, 5.0°, 6.0°, 7.0°, 8.0°, and 10° with respect to each other. Assuming that the superconductivity is BCS‐type and the invariance of the Cooper pairing potential, a maximum superconducting temperature TC ≈1.8 K is predicted for a magic angle of 0.5° between the two bilayers, increasing the superconducting transition temperature from the experimentally measured value of 0.53 mK for the Wyckoff structure of crystalline bismuth.

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Possible superconductivity in Bismuth (111) bilayers. Their electronic and vibrational properties from first principles

Cited by 5 publications

References 18 publications

Could Negative Pressures Turn Bismuth into a Metal? The Case of the Expanded

Could Negative Pressures Turn Bismuth into a Metal? The Case of the Expanded

A facile approach to calculating superconducting transition temperatures in the bismuth solid phases

Superconductivity in Twisted Bismuth Bilayers

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