Discovery of High-Temperature Superconductivity (<i>T</i><sub>c</sub> = 55 K) in B-Doped Q-Carbon

Bhaumik, Amiya; Sachan, Ritesh; Gupta, Siddharth

doi:10.1021/acsnano.7b06888

Cited by 78 publications

(66 citation statements)

References 32 publications

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“…We hope that the observation of superconductivity with very high Tc(s) found at high pressures will generate interest for further theoretical and experimental efforts concentrated on the search for high temperature conventional superconductors at ambient pressure, for example, in carbon-based materials 11 . One encouraging example is the discovery of superconductivity with Tc  55 K in Q-carbon 26 . GPa displaying Tc of 244 K, which shifts to 249 K when the pressure is increased up to 151 GPa (orange curve); dark yellow curve corresponds to the sample heated under 135 GPa with a Tc of 245 K; blue curve corresponds to a sample heated under 150 GPa with Tc 249 K. Red, orange and dark yellow curves show the sharpest transitions to zeroresistance upon cooling.…”

mentioning

confidence: 99%

Superconductivity at 250 K in lanthanum hydride under high pressures

Дроздов

Kong

Minkov

et al. 2019

Nature

1,310

1,079

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The discovery of superconductivity at 203 K in H3S 1 brought attention back to conventional superconductors whose properties can be described by the Bardeen-Cooper-Schrieffer (BCS) and the Migdal-Eliashberg theories. These theories predict that high, and even room temperature superconductivity (RTSC) is possible in metals possessing certain favorable parameters such as lattice vibrations at high frequencies. However, these general theories do not suffice to predict real superconductors. New superconducting materials can be predicted now with the aid of first principles calculations based on Density Functional Theory (DFT). In particular, the calculations suggested a new family of hydrides possessing a clathrate structure, where the host atom (Ca, Y, La) is at the center of the cage formed by hydrogen atoms 2-4 . For LaH10 and YH10 superconductivity, with critical temperatures Tc ranging between 240 and 320 K is predicted at megabar pressures 3-6 . Here, we report superconductivity with a record Tc  250 K within the Fm3m structure of LaH10 at a pressure P  170 GPa. We proved the existence of superconductivity at 250 K through the observation of zero-resistance, isotope effect, and the decrease of Tc under an external magnetic field, which suggests an upper critical magnetic field of 120 T at zerotemperature. The pressure dependence of the transition temperatures Tc (P) has a maximum of 250-252 K at the pressure of about 170 GPa. This leap, by  50 K, from the previous Tc record of 203 K 1 indicates the real possibility of achieving RTSC (that is at 273 K) in the near future at high pressures and the perspective of conventional superconductivity at ambient pressure.

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mentioning

confidence: 99%

Superconductivity at 250 K in lanthanum hydride under high pressures

Дроздов

Kong

Minkov

et al. 2019

Nature

1,310

1,079

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“…The flat-band condition is also favourable for superconductivity. There are many carbon based allotropes, which shows superconductivity such as intercalated graphites [65,66], K 3 C 60 [54], carbon-nano-tube [67,68], Q-Carbon [69], and twisted bilayer Graphene [70]. Theoretically, the arbitrary weak attractive interaction, U<0, is enough to allow the instability towards superconductivity [59,64], so that the strong interaction is not required.…”

Section: Impact Of Coulomb Interactionmentioning

confidence: 99%

Topological carbon allotropes: knotted molecules, carbon-nano-chain, chainmails, and Hopfene

Saito

Tomita

2020

Mater. Res. Express

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Carbon allotropes such as diamond, nano-tube, Fullerene, and Graphene were discovered and revolutionised material sciences. These structures have unique translational and rotational symmetries, described by a crystallographic group theory, and the atoms are arranged at specific rigid positions in 3-dimensional (D) space. Regardless of these exotic molecular structures, the structures of materials are topologically trivial in a mathematical sense, that their bonds are connected without a link nor a knot. These days, the progress on the synthetic chemistry is significant to make various topologically non-trivial molecular structures. Topological molecules (0D) including Trefoil knots, a Hopf-link, a Möbius strip, and Borromean rings, were already realised. However, their potentially exotic electronic properties have not been sufficiently explored. Here, we propose a new 3D carbon allotrope, named Hopfene, which has periodic arrays of Hopf-links to knit horizontal Graphene sheets into vertical ones without connecting by σ bonds. We conducted an ab inito band structure calculation using a Density-Functional-Theory (DFT) for Hopfene, and found that it is well-described by a tightbinding model. We confirmed the original Dirac points of 2D Graphene were topologically protected upon the introduction of the Hopf links, and low-energy excitations are described by 1D, 2D, and 3D gapless Fermions.

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“…К настоящему времени наиболее высокие температуры перехода в сверхпроводящее состояние (∼ 55 K) обнаружены у пленок, получен-ных путем импульсного лазерного сплавления тонких чередующихся нанослоев В и алмазоподобного С [3]. Борсодержащие пленки С кроме сверхпроводящих характеристик могут проявлять целый комплекс ин-тересных электрофизических, оптических и механических свойств [4], которые обусловливают интенсивное развитие исследований тонкопле-ночных (наномасштабированных) метастабильных материалов CB x на-ряду с изучением " массивных", в том числе микроструктурированных, материалов на основе гетероалмазов.…”

Section: поступило в редакцию 2 марта 2018 гunclassified

“…Можно отметить гибкость метода в получении различных по локальному состоянию алмазоподобных структур и возможность варьирования отношения В/С в широких пределах. Анализ результатов ряда работ (например, [3,4]) показал, что интересные и важные свойства пленок CB x могут реализоваться в метастабильных состояниях, для формирования которых не требу-ется экстремальной неравновесности процессов. Скорость охлаждения жидкой фазы, используемой для получения сверхпроводящих пенок из смеси С−В в [3], может составлять ∼ 10 10 K/s [7].…”

Section: поступило в редакцию 2 марта 2018 гunclassified

“…Анализ результатов ряда работ (например, [3,4]) показал, что интересные и важные свойства пленок CB x могут реализоваться в метастабильных состояниях, для формирования которых не требу-ется экстремальной неравновесности процессов. Скорость охлаждения жидкой фазы, используемой для получения сверхпроводящих пенок из смеси С−В в [3], может составлять ∼ 10 10 K/s [7]. Диссипация энергии при охлаждении паровой фазы (конденсация лазерного факела) и в тепловых пиках (внедрение ионов лазерного факела) протекает гораздо быстрее [7,8], если ИЛО проводится при нормальных условиях.…”

Section: поступило в редакцию 2 марта 2018 гunclassified

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Влияние бора на структуру и проводимость тонких пленок, получаемых лазерной абляцией алмаза при 700-=SUP=-o-=/SUP=-C

Романов¹,

Фоминский²,

Zinin³

et al. 2018

Письма В Журнал Технической Физики

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Structural features of CB_ x films obtained by pulsed laser ablation of targets made of pressed diamond powder with boron-powder additions at B/C atomic ratio of x = 0.33 have been studied. The films were deposited on heated substrates, so that diffusion processes involving C and B atoms on the surface and in the volume of films were possible. Selected conditions of film deposition ensured their effective doping with boron (0.4 ≤ x ≤ 0.6). The incorporation of B atoms was accompanied by the formation of B–C chemical bonds, whereas the formation of sp ^2 graphite bonds and their ordering in clusters with laminar packing was suppressed. The films possessed very low resistivity (~1.4 mΩ cm) at room temperature and exhibited metallic type of conductance on decreasing the temperature to 77 K.

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Discovery of High-Temperature Superconductivity (T_c = 55 K) in B-Doped Q-Carbon

Cited by 78 publications

References 32 publications

Superconductivity at 250 K in lanthanum hydride under high pressures

Superconductivity at 250 K in lanthanum hydride under high pressures

Topological carbon allotropes: knotted molecules, carbon-nano-chain, chainmails, and Hopfene

Влияние бора на структуру и проводимость тонких пленок, получаемых лазерной абляцией алмаза при 700-=SUP=-o-=/SUP=-C

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Discovery of High-Temperature Superconductivity (Tc = 55 K) in B-Doped Q-Carbon

Cited by 78 publications

References 32 publications

Superconductivity at 250 K in lanthanum hydride under high pressures

Superconductivity at 250 K in lanthanum hydride under high pressures

Topological carbon allotropes: knotted molecules, carbon-nano-chain, chainmails, and Hopfene

Влияние бора на структуру и проводимость тонких пленок, получаемых лазерной абляцией алмаза при 700-=SUP=-o-=/SUP=-C

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Discovery of High-Temperature Superconductivity (T_c = 55 K) in B-Doped Q-Carbon