Negative Oxygen Isotope Effect on the Static Spin Stripe Or - PowerPoint Presentation

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Negative Oxygen Isotope Effect on the Static Spin Stripe Or - PPT Presentation

1875 Ba 0125 CuO 4 Z Guguchia 1 R Khasanov 2 M Bendele 1 E Pomjakushina 3 K Conder 3 A Shengelaya 4 and H Keller 1 1 PhysikInstitut der Universität Zürich Switzerland ID: 413542

guguchia phys stripe rev phys guguchia rev stripe prl isotope effect la1 spin order pressure 125cuo4 superconductivity physics 875ba0

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Slide1

Negative Oxygen Isotope Effect on the Static Spin Stripe Order in La1.875Ba0.125CuO4

Z. Guguchia,1 R. Khasanov,2 M. Bendele,1E. Pomjakushina,3 K. Conder,3 A. Shengelaya,4 and H. Keller11Physik-Institut der Universität Zürich, Switzerland2Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Switzerland3Laboratory for Developments and Methods, Paul Scherrer Institute, Switzerland 4Department of Physics, Tbilisi State University, Georgia

Tbilisi State UniversitySlide2

Zurab Guguchia

Physik-Institut der Universität Zürich, SwitzerlandLaboratory for Muon Spin Spectroscopy, Paul-Scherrer Institut, Switzerland

Negative Oxygen Isotope Effect on the Static Spin Stripe Order in La

1.875

Ba0.125CuO4Slide3

Thank you!

Markus BendeleHugo KellerLaboratory for Muon Spin Spectroscopy (PSI)

Rustem Khasanov

Laboratory for Developments and Methods

(PSI)

Ekaterina Pomjakushina

Kazimierz Conder

Alexander Shengelaya

Tbilisi State UniversitySlide4

Outline Introduction Stripe phase in cuprates. Isotope effects. Muon Spin Rotation (µSR) technique.

Results Oxygen Isotope Effect (OIE) on superconductivity in LBCO-1/8. OIE on the static spin stripe order in LBCO-1/8.Pressure effects in LBCO-1/8.ConclusionsSlide5

Superconductivity in La2-xBaxCuO4

Moodenbaugh et al, Phys. Rev. B 38, 4596 (1988).

Axe

et al

, Phys. Rev. Lett.

, 2751 (1989)

ücker

et al

, Phys. Rev. B

, 104506

(2011). Slide6

Experimental evidence for static stripes in La1.48Nd0.4Sr0.12CuO

4Neutron ScatteringTranquada et al, Nature (London) 375, 561 (1995). Guguchia, PhD thesis,University of Zürich (2013).

Real space

Spin order

Charge order

M. Vojta, Adv. Phys.

, 699 (2009) and references therein.

T. Wu et. al., Nature

477

, 191 (2011).Slide7

Central issues in Cuprates What is microscopic origin of the stripe formation?

The stripe phase may be caused by electronic and/or electron-lattice interaction. Do stripes promote or inhibit superconductivity?Zaanen and Gunnarson Phys. Rev. B 40, 7391 (1989).

White and Scalapino, PRL 80, 1272 (1998).

Emery and Kivelson, Physica C

209

, 597 (1993).

M. Vojta, Adv. Phys.

, 699 (2009).

Do they contain all ingredients

required for stripe formation?Slide8

Superconductivity in La2-xBaxCuO4

Moodenbaugh et al, Phys. Rev. B 38, 4596 (1988).

0.11 <

≤

0.13

Axe

et al

, Phys. Rev. Lett. 62, 2751 (1989). Hücker et al, Phys. Rev. B

, 104506

(2011).

Slide9

Experimental evidence for static stripes: Neutron Scattering

Tranquada et al, Nature (London) 375, 561 (1995). Zaanen and Gunnarson, PRB 40, 7391 (1989).White and Scalapino, PRL 80, 1272 (1998).

1.48

Nd0.4

Sr0.12CuO4

Momentum space

Real space

Spin peaks

Charge peaksSlide10

Central issues in Cuprates What is microscopic origin of the stripe formation?

Do stripes promote or inhibit superconductivity?Slide11

Early stripe predictions

Zaanen and GunnarsonPhys. Rev. B 40, 7391 (1989)Hubbard modelMean-field solution

White and Scalapino,

PRL 80, 1272 (1998)

t-J model

Density matrix renormalization groupSlide12

Alternative: Frustrated Phase Separation

Löw, Emery, Fabricius, andKivelson, PRL 72, 1918 (1994)

Competing interactions result in striped and checkerboard phases

Analysis of t-J model by Emery and Kivelson:

Holes tend to phase separate!

t-J model lacks long-range part of Coulomb interaction

Long-range Coulomb repulsion frustrates phase separationSlide13

Holes in an AF : Why Do Stripes Occur?

PHASE SEPARATION

Coulomb Interactions

Kinetic Energy

Frustration

STRIPES

Emery and Kivelson Physica C

209

, 597 (1993).

The investigated models do not contain all ingredients

required for stripe formation!Slide14

Stripe order in La1.875Ba0.125CuO4

M. Hücker et al., Phys. Rev. B 83, 104506 (2011).

Z. Guguchia et al.

, New Journal of Physics 15, 093005 (2013).

Maisuradze and Guguchia,

University of Zurich. Slide15

sc(0) + Vm(0) ≈ 1

Superconductivity and magnetism are competing order parameters.

Phase diagrams

Z. Guguchia

et al.

, New Journal of Physics

, 093005 (2013).Slide16

Diamond anvil cell for high-pressure magnetization measurements

Maisuradze and Guguchia, University of Zurich. Slide17

Superconducting properties of La1.875Ba0.125CuO4

Guguchia et al., New Journal

Physics 15, 093005 (2013).Slide18

ücker et al, PRL 104, 057004 (2010).Slide19

Double wall piston-cylinder type of cell made of MP35N material for µSR under pressure

Andreica, Ph.D. thesis, IPP/ETH-Zürich, (2001). Slide20

High pressure µSR experiments on La1.875Ba0.125CuO4

Z. Guguchia et al., New Journal of Physics 15, 093005 (2013).Slide21

High pressure µSR experiments on La1.875Ba0.125CuO4

TLTT = 0

Guguchia

al.

, New Journal

of Physics 15, 093005 (2013).Slide22

Conventional superconductivity

Electron-phonon interactionBCS:

Isotope effect:

Ranges from 0.2-0.5 in elemental metals

Weak coupling BCS predicts a value of

= 0.5

C.A. Reynolds et. al., Phys. Rev.

, 487 (1950).

E. Maxwell, Phys. Rev.

, 477 (1950).

J. Bardeen et. al., Phys. Rev.

108

, 1175 (1957).Slide23

Unconventional Oxygen Isotope effects (OIE’s) in cuprates

J. Hofer et. al., PRL 84, 4192 (2000).K.A. Müller, J. Phys. Condens. Matter 19, 251002 (2007).H. Keller et. al., Materials today 11, 9 (2008).

Shengelaya

et. al, PRL 83, 24 (1999).

Khasanov

et. al., PRL 101, 077001 (2008).

Lanzara

et. al., J. Phys. Condens. Matter 11, L541 (1999). Rubio Temprano et. al., PRL 84, 1990 (2000).Zhech et. al., Nature 371, 681–683, 1994. Slide24

Isotope effect on Tc near 1/8

M.K. Crawford et. al., Science 250, 1390 (1990). G.M. Zhao et. al., J. Phys.: Condens. Matter 10, 9055 (1998).J.P. Franck et. al., PRL 71, 283 (1993). J. Hofer et. al., PRL 84, 4192 (2000).B. Batlogg et. al., PRL 59, 912 (1987). G.Y. Wang et. al., PRB 75, 212503 (2007).Slide25

TRIUMF http://neutron.magnet.fsu.edu/muon_relax.htmlMuon-spin rotation (

μSR) techniqueSlide26

Courtesy of H. Luetkens

homogeneous

amplitude

→ magnetic volume fraction

frequency

→ average local magnetic field Damping → magnetic field distribution / magnetic fluctuations

time (

SR in magnetic materials

inhomogeneousSlide27

Magnetization experiments

Tranquada et. al., PRB 78, 174529 (2008). Li et. al., PRL 99, 067001 (2007).Z. Guguchia et al., New Journal of Physics 15, 093005 (2013)

Z. Guguchia

et al.

Phys. Rev.

Lett. (2014).Slide28

Magnetization experiments

Tranquada et. al., PRB 78, 174529 (2008). Li et. al., PRL 99, 067001 (2007).Slide29

Isotope effect on Tc in La1.875Ba0.125

CuO4 Z. Guguchia et al., Phys. Rev. Lett. (2014).Slide30

Oxygen Isotope effect on Tso

Z. Guguchia et al., Phys. Rev. Lett. (2014).Slide31

Oxygen Isotope effect on

Tso Z. Guguchia et al., Phys. Rev. Lett. (2014).Slide32

G.M. Luke et. al., Physica C

185-9, 1175 (1991).B. Nachumi et. al., PRB 58, 8760 (1998).Oxygen Isotope effect on Tso

Z. Guguchia

et al.

Phys. Rev. Lett. (2014).Slide33

+Slide34

OIE effect on Tso and magnetic fraction Vm

Z. Guguchia et al., Phys. Rev. Lett. (2014).Slide35

Summary of the OIE studies on La1.875Ba0.125CuO4

Give evidence for stripe-lattice coupling in cuprates.Superconductivity and stripe order are competing phenomena.Slide36

Pressure experiments with SQUID and µSR

Z. Guguchia et al., New Journal of Physics 15, 093005 (2013).

SQUID (

Maisuradze

and Guguchia)µSR

(R. Khasanov)Slide37

Pressure effect on static spin-stripe order in La1.875Ba0.125CuO4

Vsc(0) + Vm(0) ≈ 1

Z. Guguchia

et al.

, New Journal of Physics 15, 093005 (2013).Slide38

LTT structural phase under pressure

Hücker et al, PRL 104, 057004 (2010).Slide39

Pressure effect on the isotope effect inLBCO-1/8Slide40

Conclusions

Large negative OIE’s were observed on Tso and Vm in La2-xBaxCuO4 (x = 1/8).Oxygen-isotope shifts of Tc and TSO are sign reversed. Stripe order and superconductivity are competing orders.

The electron-lattice interaction is involved in the stripe formation and is a crucial factor controlling the competition between the stripe order and superconductivity.

A purely electronic

mechanism can not explain the present isotope and pressure experiments!Slide41

Thank you very much

for your attention!Slide42
Slide43

Superconducting properties of La1.875Ba0.125CuO4

Diamond anvil cell for high-pressure measurements.

Dr. A. Maisuradze, University of Zurich. Slide44
Slide45

M. H

ücker et. al., PRL 104, 057004 (2010).Slide46

B. Nachumi

et. al., PRB 58, 8760 (1998).Slide47
Slide48

LTO→LTT ≈ 50 K