<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ca</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mi mathvariant="normal">Ti</mml:mi><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mr

Bednorz, J. G.; Müller, K. A.

doi:10.1103/physrevlett.52.2289

Cited by 737 publications

(390 citation statements)

References 18 publications

Supporting

Mentioning

363

Contrasting

Unclassified

Order By: Relevance

“…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 .…”

mentioning

confidence: 99%

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

Rischau¹,

Lin²,

Grams³

et al. 2017

Nature Phys

213

230

View full text Add to dashboard Cite

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...

show abstract

mentioning

confidence: 99%

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

Rischau¹,

Lin²,

Grams³

et al. 2017

Nature Phys

213

230

View full text Add to dashboard Cite

show abstract

“…This was corroborated since small doping content promotes ferroelectricity. 374 The ST is prone to display AFD distortions 375 due to the small ionic radii of Sr 2+ . 371 The BNT-ST displays a R structure at room temperature below 20 mol % ST. 363,365 Increasing ST content leads to a gradual increase in the lattice parameter between 3.885 Å and 3.905 Å.…”

Section: Atomic Structurementioning

confidence: 99%

Strain Mechanisms in Lead-Free Ferroelectrics for Actuators

Acosta

2016

Springer Theses

View full text Add to dashboard Cite

“…Its dielectric constant saturates at a high level, 1 0 < 20000 [1], associated with the softening of a long-wavelength transverse optic phonon mode. The application of uniaxial stress and proper substitution of the A-site ions can significantly destabilize the lattice, and induce a ferroelectric phase transition [4][5][6]. In addition, a crossover from quantum ferroelectric to relaxor behavior may occur as observed, e.g., in (Sr 1-1.5x Bi x )TiO 3 for x .…”

Section: Introductionmentioning

confidence: 99%

Phase transition and random-field induced domain wall response in quantum ferroelectrics SrTi¹⁸O₃: review and perspective

Itoh

Yagi

Uesu

et al. 2004

Science and Technology of Advanced Materials

View full text Add to dashboard Cite

The oxygen isotope exchange of 16 O by 18 O in SrTiO 3 causes a drastic change from paraelectric to ferroelectric, due to the suppression of quantum fluctuation. The phase transition and origin of the huge domain wall response were evaluated by dielectric, magnetic (NMR), and optical measurements (SHG, light scattering). The results obtained corroborate (1) smeared ferroelectric transition at T c due to quenched random field, (2) a quite large dielectric contribution from domain walls, (3) incomplete softening of the transverse optic mode, and (4) a large contribution from the relaxational mode to the phase transition. Quantitative explanations, given to individual results, may give hints to grasp the mechanism for the evolution of ferroelectricity, in which quantum fluctuation and random fields are dominant perturbations. Finally, some of the news studies on the SrTiO 3 were also introduced. q

show abstract

Sr1−xCaxTiO

Cited by 737 publications

References 18 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

Strain Mechanisms in Lead-Free Ferroelectrics for Actuators

Phase transition and random-field induced domain wall response in quantum ferroelectrics SrTi¹⁸O₃: review and perspective

Contact Info

Product

Resources

About

Sr1−xCaxTiO

Cited by 737 publications

References 18 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

Strain Mechanisms in Lead-Free Ferroelectrics for Actuators

Phase transition and random-field induced domain wall response in quantum ferroelectrics SrTi18O3: review and perspective

Contact Info

Product

Resources

About

Phase transition and random-field induced domain wall response in quantum ferroelectrics SrTi¹⁸O₃: review and perspective