Quantum Critical Origin of the Superconducting Dome in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>SrTiO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Edge, Jonathan M.; Kedem, Yaron; Aschauer, Ulrich; Spaldin, Nicola A.; Balatsky, Alexander V.

doi:10.1103/physrevlett.115.247002

Cited by 183 publications

(178 citation statements)

References 42 publications

(66 reference statements)

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“…Both these features may be relevant to the observed enhancement in superconducting T c . Edge et al 9 have recently proposed that substituting 16 O with 18 O should drastically change the superconducting dome of n-doped SrTiO 3 . They predicted that such a substitution would enhance the highest critical temperature and shift it to lower doping.…”

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confidence: 99%

“…This provides a new input for the ongoing debate on the microscopic origin of superconductivity 4,[8][9][10] . Calcium substitution leads to a higher dielectric constant at low temperature (Fig.…”

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confidence: 99%

“…In this range of carrier concentration, exceptionally low compared to any other known superconductor, the Fermi temperature is an order of magnitude lower than the Debye temperature and the ability of phonons to form Cooper pairs is questionable 7,8 . Recent theories invoke fluctuations of the ferroelectric mode 9 , longitudinal optical phonons 10 or plasmons 8 as bosons responsible for the generation of Cooper pairs. In many unconventional superconductors, another electronic order competes with superconductivity.…”

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confidence: 99%

“…In many unconventional superconductors, another electronic order competes with superconductivity. Here, the ferroelectric order is an obvious candidate 4,9 . It emerges in SrTiO 3 by isotopic substitution of 16 O oxygen atoms with 18 O (ref.…”

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A ferroelectric quantum phase transition inside the superconducting dome of Sr1−xCaxTiO3−δ

Rischau¹,

Lin²,

Grams³

et al. 2017

Nature Phys

213

230

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SrTiO 3 , a quantum paraelectric 1 , becomes a metal with a superconducting instability after removal of an extremely small number of oxygen atoms 2 . It turns into a ferroelectric upon substitution of a tiny fraction of strontium atoms with calcium 3 . The two orders may be accidental neighbours or intimately connected, as in the picture of quantum critical ferroelectricity 4 . Here, we show that in Sr 1−x Ca x TiO 3−δ (0.002 < x < 0.009, δ < 0.001) the ferroelectric order coexists with dilute metallicity and its superconducting instability in a finite window of doping. At a critical carrier density, which scales with the Ca content, a quantum phase transition destroys the ferroelectric order. We detect an upturn in the normal-state scattering and a significant modification of the superconducting dome in the vicinity of this quantum phase transition. The enhancement of the superconducting transition temperature with calcium substitution documents the role played by ferroelectric vicinity in the precocious emergence of superconductivity in this system, restricting possible theoretical scenarios for pairing.A perovskite of the ABO 3 family, SrTiO 3 is a quantum paraelectric whose dielectric constant rises to ∼20,000 at low temperature 1 , but avoids long-range ferroelectric order. It becomes a metal by substituting Sr with La, Ti with Nb, or by removing O. It has been known for half a century that this metal is a superconductor at low temperatures 2 . More recently, a sharp Fermi surface and a superconducting ground state have been found to persist down to a carrier concentration of 10 17 cm −3 in SrTiO 3−δ (refs 5,6 However, mobile electrons screen polarization and therefore only insulating solids are expected to host a ferroelectric order. Hitherto, as a paradigm, ferroelectric quantum criticality, in contrast to its magnetic counterpart, was deprived of an experimental phase diagram in which a superconducting phase and a ferroelectric order share a common boundary.Here, we produce such a phase diagram in the case of Sr 1−x Ca x TiO 3−δ . The main new observations are the following: metallic Sr 1−x Ca x TiO 3−δ hosts a phase transition structurally indistinguishable from the ferroelectric phase transition in insulating Sr 1−x Ca x TiO 3 ; the coexistence between this ferroelectric-like order and superconductivity ends beyond a threshold carrier concentration; and, in the vicinity of this quantum phase transition, calcium substitution enhances the superconducting critical temperature and induces an upturn in the normal-state resistivity.Figure 1 summarizes what we know about the emergence of ferroelectricity, metallicity and superconductivity in this system. When a small fraction of Sr atoms (x > 0.002) is replaced with isovalent Ca, Sr 1−x Ca x TiO 3 becomes ferroelectric 3 , with a Curie temperature steadily increasing with Ca content in the dilute limit 0.002 < x < 0.02 (refs 3,13,14). Macroscopic polarization below the Curie temperature has been observed in dielectric and linear birefringence measurements, a...

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confidence: 99%

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confidence: 99%

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confidence: 99%

mentioning

confidence: 99%

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A ferroelectric quantum phase transition inside the superconducting dome of Sr1−xCaxTiO3−δ

Rischau¹,

Lin²,

Grams³

et al. 2017

Nature Phys

213

230

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“…During last five decades, much attention has been given to the electronic transport mechanisms in doped SrTiO 3 . This is special due to the anomalous superconductivity within a limited doping window [9][10][11] in the vicinity of a ferroelectric transition 12 . Stoichiometric SrTiO 3 is an insulator with 3.2 eV band gap, but one can introduce electron donor states by replacing Ti 4+ by Nb +513 or Sr 2+ by La 3+ like a n-type silicon based semiconductor 14 either oxygen can be removed with heat treatment in vacuum at high temperatures in order to reach SrTiO 3-δ vacancy self-doped semiconductors 15 .…”

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Kinetics of Vacancy Doping in SrTiO3 Studied by in situ Electrical Resistivity

et al. 2018

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The kinetics of annealing to transform stoichiometric SrTiO 3 insulator into a vacancy-doped semiconductor-superconductor was revisited by in situ electrical resistivity measurements. SrTiO 3 single crystals were grown by Floating Zone Method. Using a homemade apparatus several electrical resistivity as a function of time were measured at different temperatures, which allows one to study the creation of vacancies during annealing under vacuum. The activation energy for the oxygen vacancies formation/charge doping in SrTiO 3 was estimated as 1.4±0.3 eV using solid-state kinetics approach.

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Ferroelectricity‐Tuned Band Topology and Superconductivity in 2D Materials and Related Heterostructures

Chen,

Cui,

Zhang

2024

Adv Funct Materials

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Ferroelectricity, band topology, and superconductivity are respectively local, global, and macroscopic properties of quantum materials, and understanding their mutual couplings offers unique opportunities for exploring rich physics and enhanced functionalities. In this mini‐review, the attempt is to highlight some of the latest advances in this vibrant area, focusing in particular on ferroelectricity‐tuned superconductivity and band topology in 2D materials and related heterostructures. First, results from predictive studies of the delicate couplings between ferroelectricity and topology or superconductivity based on first‐principles calculations and phenomenological modeling are presented, with ferroelectricity‐enabled topological superconductivity as an appealing objective. Next, the latest advances on experimental studies of ferroelectricity‐tuned superconductivity based on different 2D materials or van der Waals heterostructures are covered. Finally, as perspectives, schemes are outlined that may allow to materialize new types of 2D systems that simultaneously harbor ferroelectricity and superconductivity, or that may lead to enhanced ferroelectric superconductivity, ferroelectric topological superconductivity, and new types of superconducting devices such as superconducting diodes.

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Quantum Critical Origin of the Superconducting Dome inSrTiO3

Cited by 183 publications

References 42 publications

A ferroelectric quantum phase transition inside the superconducting dome of Sr1−xCaxTiO3−δ

A ferroelectric quantum phase transition inside the superconducting dome of Sr1−xCaxTiO3−δ

Kinetics of Vacancy Doping in SrTiO3 Studied by in situ Electrical Resistivity

Ferroelectricity‐Tuned Band Topology and Superconductivity in 2D Materials and Related Heterostructures

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