Superconducting critical temperature under pressure

González-Pedreros, G. I.; Baquero, R.

doi:10.1016/j.physc.2018.01.015

Cited by 9 publications

(9 citation statements)

References 44 publications

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“…Experimentally it was confirmed that H 3 S superconductor behavior originates from electron-phonon interactions [2]. In electron-phonon superconductors, pressure affects the vibration spectrum and electron-phonon interaction by shifting it to higher frequencies which can enhance or lower the critical temperature depending on details of the system under study [4]. This has been put in evidence by several experimental works [5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 93%

“…In this paper, we report a theoretical study of pressure effects on the conventional superconductor H 3 S by first-principles calculations for the pressure range where the T c was measured (155-225 GPa). The effects of pressure on T c are incorporated using the Functional Derivative Method (FDM) [4]. The D cp (ω, T c ) is determined following the procedure proposed by González-Pedreros et al [19].…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, the µ * parameter requires attention, due it has not been yet neither calculated nor measured with enough precision to be useful as the parameter needed to solve the linearized Migdal-Eliashberg equations (LMEE) to obtain an accurate value for T c . But, if experimental T c is known, then by solving the LMEE it is possible to fit µ * [3,4].…”

Section: Introductionmentioning

confidence: 99%

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High-T _c superconductivity in H₃S: pressure effects on the superconducting critical temperature and Cooper pair distribution function

Camargo-Martínez¹,

González-Pedreros²,

Baquero³

2019

Supercond. Sci. Technol.

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We use first-principles calculations to study pressure effects on the vibrational and superconducting properties of H 3 S in the cubic Im3m phase for the pressure range where the superconducting critical temperature (T c ) was measured (155-225 GPa). The pressure effects were incorporated using the Functional Derivative Method (FDM). In this paper, we present for the first time, the Cooper-Pairs Distribution Functions D cp (ω, T c ) for H 3 S, which will allow to identify the spectral regions where Cooper-Pairs formation at temperature T c is more favorable. We analyzed in detail the pressure effects on the electron-phonon spectral density function α 2 F(ω) and phonon density of states (PhDOS) and its relationship with the pressure dependence of the T c . Our results show a good agreement with the experiment. The D cp (ω, T c ) suggests that low frequency vibration region is where Cooper-Pairs are possible, which means that S-vibration have an important role in the H 3 S superconductivity properties. The increase in pressure leads to a reduction in the coupling constant λ and an increase in Coulomb pseudopotential µ * which induces a consistent correlation with T c , in good agreement with the Migdal-Eliashberg theory.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-T _c superconductivity in H₃S: pressure effects on the superconducting critical temperature and Cooper pair distribution function

Camargo-Martínez¹,

González-Pedreros²,

Baquero³

2019

Supercond. Sci. Technol.

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“…At the range pressures of , the superconducting critical temperature Niobium undergoes a decrease with an ulterior raising 3 , namely Nb anomaly. The tendency change happens at , approximately 3 , 15 . Nevertheless, electronic band structure and Fermi surface do not suggest any evident relationship with the Nb anomaly 4 , 16 – 24 .…”

Section: Resultsmentioning

confidence: 97%

Cooper Pairs Distribution function for bcc Niobium under pressure from first-principles

González-Pedreros

Camargo-Martínez²,

Mesa

2021

Sci Rep

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In this paper, we report Cooper Pairs Distribution function $${D}_{cp}(\omega ,{T}_{c})$$ D cp ( ω , T c ) for bcc Niobium under pressure. This function reveals information about the superconductor state through the determination of the spectral regions for Cooper-pairs formation. $${D}_{cp}(\omega ,{T}_{c})$$ D cp ( ω , T c ) is built from the well-established Eliashberg spectral function and phonon density of states, calculated by first-principles. $${D}_{cp}(\omega ,{T}_{c})$$ D cp ( ω , T c ) for Nb suggests that the low-frequency vibration region $$\left(\omega <6 \,{\text{meV}}\right)$$ ω < 6 meV is where Cooper-pairs are possible. From $${D}_{cp}(\omega ,{T}_{c})$$ D cp ( ω , T c ) , it is possible to obtain the $${N}_{cp}$$ N cp parameter, which is proportional to the total number of Cooper-Pairs formed at a temperature $${T}_{c}$$ T c . The $${N}_{cp}$$ N cp parameter allows an approach to the understanding of the Nb $${T}_{c}$$ T c anomalies, measured around 5 and 50 GPa.

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“…The discovery of new critical temperatures of superconductors under pressure has been numerous in recent years, for example sulfur hydride with T c of about 200 kelvin under pressure of about 56 GPa [3]. In addition, some theoretical researches have been carried out to calculate the critical temperature as a function of pressure based on the Eliashberg spectral function [4]. The understanding of how pressure affects the critical temperature of a superconductor can be used to improve the theoretical calculations to be more reliable and more comparable to the experimental result values.…”

Section: Introductionmentioning

confidence: 99%

Analysis of superconducting critical temperature using numerical method

Rientong,

Natkunlaphat,

Pinsook

2023

J. Phys.: Conf. Ser.

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Currently, many studies have shown that the critical temperature (Tc) of a superconductor can be predicted by using the BCS theory. In this work, we analyse Tc of superconductors, which is determined by the spectral function (α2F(ω)) derived from the interaction between electrons and phonons. The equation that we used for the calculation is T c strong = f 1 f 2 T c weak . In this equation, T c weak refers to the Allen-Dynes formula and f is the correction factor. We compare the Tc obtained from this equation with our method. Many important parameters are given and analysed, such as average coupling strength (λ), the square root of the average frequency square (ω2), and average logarithm frequency (ωln). We use numerical methods and expect to improve the equation to calculate Tc to be user-friendly. Normally, the calculation of Tc can be challenging and time-consuming. The most successful theory explaining the general properties of superconductors is the BCS theory. It explains the mechanism in which normal conductors become superconductors, and the pairing of electrons known as the Cooper pairing is formed by the electron-phonon interactions. In the past, the BCS theory predicted the limit of the critical temperature of superconductors to be around 30-40 kelvin. Recently, several researchers have been discovered a higher Tc value than the limited value from experiments under high pressure. Our method could provide a better analysis of appropriate Tc of superconductors to support new discoveries in the future.

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Superconducting critical temperature under pressure

Cited by 9 publications

References 44 publications

High-T _c superconductivity in H₃S: pressure effects on the superconducting critical temperature and Cooper pair distribution function

High-T _c superconductivity in H₃S: pressure effects on the superconducting critical temperature and Cooper pair distribution function

Cooper Pairs Distribution function for bcc Niobium under pressure from first-principles

Analysis of superconducting critical temperature using numerical method

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Superconducting critical temperature under pressure

Cited by 9 publications

References 44 publications

High-T c superconductivity in H3S: pressure effects on the superconducting critical temperature and Cooper pair distribution function

High-T c superconductivity in H3S: pressure effects on the superconducting critical temperature and Cooper pair distribution function

Cooper Pairs Distribution function for bcc Niobium under pressure from first-principles

Analysis of superconducting critical temperature using numerical method

Contact Info

Product

Resources

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High-T _c superconductivity in H₃S: pressure effects on the superconducting critical temperature and Cooper pair distribution function

High-T _c superconductivity in H₃S: pressure effects on the superconducting critical temperature and Cooper pair distribution function