Ferroelectric quantum criticality and enhanced superconductivity in plastically deformed strontium titanate

The properties of quantum materials are commonly tuned using experimental variables such as pressure, magnetic field and doping. Here we explore a different approach: irreversible, plastic deformation of single crystals. We show for the superconductor SrTiO 3 that compressive plastic deformation induces low-dimensional superconductivity significantly above the superconducting transition temperature ( T c ) of undeformed samples, with evidence of superconducting correlations at temperatures two orders of magnitude above the bulk T c . The superconductivity enhancement is correlated with the appearance of self-organized dislocation structures, as revealed by diffuse neutron and X-ray scattering. We also observe signatures of deformation-induced quantum-critical ferroelectric fluctuations and inhomogeneous ferroelectric order via Raman scattering. These results suggest that the strain surrounding the self-organized dislocation structures induces local ferroelectricity and quantum-critical dynamics that strongly influence T c , consistent with a theory of superconductivity enhanced by soft polar fluctuations. More broadly, our results demonstrate the promise of plastic deformation and dislocation engineering as tools to manipulate electronic properties of quantum materials.

[1]  J. Zuo,et al.  Two-dimensional superconductivity and anisotropic transport at KTaO3 (111) interfaces , 2021, Science.

[2]  M. Krogstad,et al.  Enhanced superconductivity in plastically deformed strontium titanate , 2020 .

[3]  M. Gastiasoro,et al.  Anisotropic superconductivity mediated by ferroelectric fluctuations in cubic systems with spin-orbit coupling , 2020, Physical Review B.

[4]  M. Gastiasoro,et al.  Superconductivity in dilute SrTiO3: A review , 2019, 1912.01509.

[5]  Le Van Lich,et al.  Periodically-arrayed ferroelectric nanostructures induced by dislocation structures in strontium titanate. , 2019, Physical chemistry chemical physics : PCCP.

[6]  F. Légaré,et al.  Second Harmonic Generation Investigation of Symmetry Breaking and Flexoelectricity Induced by Nanoindentations in SrTiO3 , 2019, Advanced Functional Materials.

[7]  C. Leighton,et al.  Universal superconducting precursor in three classes of unconventional superconductors , 2019, Nature Communications.

[8]  C. Haines,et al.  Pressure dependence of ferroelectric quantum critical fluctuations , 2019, Physical Review B.

[9]  S. Stemmer,et al.  Enhancing superconductivity in SrTiO3 films with strain , 2019, Science Advances.

[10]  C. Rischau,et al.  Possible mechanism for superconductivity in doped SrTiO3 , 2019, Physical Review Research.

[11]  J. Vaughey,et al.  Reciprocal space imaging of ionic correlations in intercalation compounds , 2019, Nature Materials.

[12]  J. Ruhman,et al.  Superconductivity near a Ferroelectric Quantum Critical Point in Ultralow-Density Dirac Materials , 2019, Physical Review X.

[13]  M. Gastiasoro,et al.  Low-temperature specific heat of doped SrTiO3 : Doping dependence of the effective mass and Kadowaki-Woods scaling violation , 2018, Physical Review Materials.

[14]  A. Balatsky,et al.  Strain-engineered interaction of quantum polar and superconducting phases , 2018, Physical Review Materials.

[15]  C. Rischau,et al.  Metallicity and Superconductivity in Doped Strontium Titanate , 2018, Annual Review of Condensed Matter Physics.

[16]  P. Gao,et al.  Atomic-Scale Measurement of Flexoelectric Polarization at SrTiO_{3} Dislocations. , 2018, Physical review letters.

[17]  G. Lonzarich,et al.  Superconductivity in the vicinity of a ferroelectric quantum phase transition , 2018, 1801.08121.

[18]  N. Spaldin,et al.  Strain and ferroelectric soft-mode induced superconductivity in strontium titanate , 2017, 1712.08368.

[19]  J. Levy,et al.  One-Dimensional Nature of Superconductivity at the LaAlO_{3}/SrTiO_{3} Interface. , 2017, Physical review letters.

[20]  H. Hwang,et al.  Polaronic behavior in a weak-coupling superconductor , 2016, Proceedings of the National Academy of Sciences.

[21]  T. Kitamura,et al.  Multiferroic Dislocations in Ferroelectric PbTiO3. , 2017, Nano letters.

[22]  S. Simon,et al.  Strong peak in Tc of Sr2RuO4 under uniaxial pressure , 2016, Science.

[23]  J. Rödel,et al.  Temperature‐Dependent Deformation and Dislocation Density in SrTiO3 (001) Single Crystals , 2016 .

[24]  O. Delaire,et al.  The origin of incipient ferroelectricity in lead telluride , 2016, Nature Communications.

[25]  P. Carrez,et al.  From glissile to sessile: Effect of temperature on 〈110〉 dislocations in perovskite materials , 2016 .

[26]  M. Venkatesan,et al.  Surface magnetism of strontium titanate , 2016, Journal of physics. Condensed matter : an Institute of Physics journal.

[27]  Vickie E. Lynch,et al.  Expanding Lorentz and spectrum corrections to large volumes of reciprocal space for single-crystal time-of-flight neutron diffraction , 2016, Journal of applied crystallography.

[28]  Kamran Behnia,et al.  Scalable T2 resistivity in a small single-component Fermi surface , 2015, Science.

[29]  N. Spaldin,et al.  Quantum Critical Origin of the Superconducting Dome in SrTiO_{3}. , 2015, Physical review letters.

[30]  A. Sleight.  Bismuthates: BaBiO3 and related superconducting phases , 2015 .

[31]  E. Salje,et al.  Polar correlations and defect-induced ferroelectricity in cryogenic KTaO3 , 2014 .

[32]  I. Živković,et al.  The role of lock-in phase setting in ac susceptibility measurement. , 2013, The Review of scientific instruments.

[33]  Y. Ikuhara,et al.  Ferromagnetic dislocations in antiferromagnetic NiO. , 2013, Nature nanotechnology.

[34]  M. Cazayous,et al.  Observation of incipient charge nematicity in Ba(Fe(1-x)Co(x))2As2. , 2013, Physical review letters.

[35]  A. Goldman,et al.  Indications of superconductivity at somewhat elevated temperatures in strontium titanate subjected to high electric fields , 2010 .

[36]  P. McMahon,et al.  In-Plane Resistivity Anisotropy in an Underdoped Iron Arsenide Superconductor , 2010, Science.

[37]  C. Leighton,et al.  Electronic transport in doped SrTiO3: Conduction mechanisms and potential applications , 2010 .

[38]  H. Hagemann,et al.  Electron-phonon interaction and charge carrier mass enhancement in SrTiO3. , 2007, Physical review letters.

[39]  J. Schilling.  High-Pressure Effects , 2006, cond-mat/0604090.

[40]  H. Poulsen,et al.  Formation and Subdivision of Deformation Structures During Plastic Deformation , 2006, Science.

[41]  A. Tagantsev,et al.  Room-temperature ferroelectricity in strained SrTiO3 , 2004, Nature.

[42]  P. Gumbsch,et al.  Plasticity and an inverse brittle-to-ductile transition in strontium titanate. , 2001, Physical review letters.

[43]  R. Barabash,et al.  X-ray scattering by crystals with local lattice rotation fields , 1999 .

[44]  David C. Look,et al.  Dislocation Scattering in GaN , 1999 .

[45]  Lester F. Eastman,et al.  Scattering of electrons at threading dislocations in GaN , 1998 .

[46]  E. Salje,et al.  Sheet superconductivity in twin walls: experimental evidence of , 1998 .

[47]  R. Cowley.  The phase transition of strontium titanate , 1996, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[48]  Vaglio,et al.  Explanation of the resistance-peak anomaly in nonhomogeneous superconductors. , 1993, Physical review. B, Condensed matter.

[49]  植 寛素.  Stress-induced ferrselectricity and soft phonon modes in Srtio3 , 1975 .

[50]  W. J. Burke,et al.  Stress induced ferroelectricity in SrTiO3 , 1971 .

[51]  E. R. Pfeiffer,et al.  EFFECT OF STRESS ON THE SUPERCONDUCTIVE TRANSITION TEMPERATURE OF STRONTIUM TITANATE. , 1967 .

[52]  D. Lewis.  X-ray microbeam study of deformation bands in aluminium , 1960 .

[53]  D. L. Dexter.  Scattering of Electrons in Metals by Dislocations , 1952 .

[54]  R. Honeycombe.  X-Ray Asterisms from Deformed Crystals , 1951 .