Ideas leading to discovery of High- Temperature Superconductivity in Cuprates

Vivek Kumar BhartiyaVivek.Bhartiya@skolkovotech.ru

Skolkovo Institute of Science and Technology

Cubic niobium alloys copper oxides perovskite

2

CRTITICAL PHASE DIAGRAM

Tc (K)

Al 1.2

Pb 7.2

Sn 3.7

Nb3 Sn 18

H2S 203

YBCO 90

BaFe2 As2 50

160

Conventional Superconductor

Unconventional (HTS) Superconductor

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Low temperature experimentalist- structural and ferroelectric properties of perovskite solid-solution crystal

IBM Research Division, Zurich Research Laboratory, expertise in insulating oxides

SrTiO3 & LaAlO3

J. Georg Bednorz HR@ IBM, 1978

(STM) 1986

SrTiO3 + Nb ( to increase n = 2* 1020 /cm3) Niobium reduced material instead of simply reduced, Tc = 0.7K . SrTiO3 + Nb +Nb…..1.2K

Gerd Binnig

Superconductivity and tunneling

Plasma edge passes the highest phonon - shielding

Baratoff, A. and Binnig, G. (1981) Physica 108B, 1335; Baratoff, A., Binnig, G.,Bednorz, J. G., Gervais, F., and Servoin, J. L. (1982) in: Superconductivity in dandf-Band Metals, Proceedings IV Conference on Superconductivily in d- and f-Band

Metals, editors W. Buckel and W. Weber (Kernforschungszentrum Karlsruhe)p. 419.

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T. Schneider and E. Stoll, Physica 55,702 (1971)

K. Alex Muller

Granular Superconductivity-Tc-2.8K, 1.1K in pure Al, ESR experiments on transition metal impurities in the perovskite host lattice

Possibility of High-temperature superconductivity in metallic H. 100K , 2-3 Megabar

SrTiO3 + H Not enough DOE for metallic state . 0.3K if reduced.

Hey Bednorz, would you like to work on superconductivity? (1986)

Schooley, J. F., Frederikse, H. P. R., Hosler, W. R., and Pfeiffer, E. R. (1967) Phys. Rev. 159, 301.

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1973 : Li- Ti-O system – Multiphase sample-Presence of different phases-Difficult in preparation

Johnston, D. C., Prakash, H., Zachariasen, W. H., and Viswanathan, R. (1973) Mat. Res. Bull. 8, 777.

Sleight, A. W., Gillson, J. L., and Bierstedt, P. E. (1975) Solid State Commun. 17, 27.

1975 : Single-phase sample-Single phases-Easy preparation- Thin film device applications- U.S. and Japan

Ba Pb1-x Bix O3 Tc~ 13K

Li1+x Ti2-x O4 Tc~ 13K

n= 4 * 10 21 /cm3

One can vary one of these numbers to control Tc.

05/02/2023 6Origin of High- Temperature Superconductivity, Very important slide

Chakraverty, B. K. (1979) J. Physique Lett. 40, L99; idem (1981) J. Physique 42, 1351.

λ= N(EF) V

Bipolar model based on the mixed vacancies.Jahn- Teller polaron model

Höck, K.-H., Nickisch, H., and Thomas, H. (1983) Helv. Phys. Acta 56, 237.

Linear chain model for narrow-band IMC results--

EJT << BandWidth = slight perturbation EJT < BandWidth = tendency to localizationEJT ~ |BandWidth| = polaron

Now question was, in which systems to look for superconductive transition????

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Ni3+ , Fe3+ , Cu2+ - partially filled (eg) oxides

1983

La-Ni-O, LaNiO3 , metallic conductor

La-Al- Ni-O, La Al1-xNixO3 , localization at low temp

La-Y- Ni-O, Lax Al1-xNiO3 , localization at low temp

Would the path we decided to embark upon finally lead into a blind alley?

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Ni3+ , Fe3+ , Cu2+ - partially filled (eg) oxides

1985

La-Ni-O, LaNiO3 , metallic conductor

La-Non JT Cu2+ - Ni-O, La Cu1-xNixO3, increased absolute value of resistance

However, the metallic character of the solid solutions was preserved down to 4K. No indication of superconductivity. Time to study literature.

Received new experimental support

Goodenough, J. B. and Longo, M. (1970, “Magnetic and other properties of oxide and related compounds” In: Landoldt-Boernstein New Series. Vol. III/4a:

Crystal and Solid State Physics, editors K. H. Hellwege and A. M. Hellwege(Springer-Verlag, Berlin, Heidelberg, New York), p. 262, Fig. 73.

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Michel, C., Er-Rakho, L., and Raveau, B. (1985) Mat. Res. Bull. 20, 667.

Ba- La-Cu perovskite exhibiting metallic conductivity in the temperature range 300-1000 C.

All four property fulfilled by this material

x Ba 0.75

Suzuki, M., Murakami, T., and Inamura, T. (1981) Shinku 24, 67; Enomoto,Y., Suzuki, M., Murakami, T., Inukai, T., and Inamura, T. (1981) Jpn. J.

Appl. Phys. 20, L661.

Decrease in resistance shows similarity with superconductivity in granular materials.

X-Ray diffraction pattern of two-phase sample with Ba : La = 0.08. The second phase occurring with the K2NeF-type phase indicated by open circles.

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“I turned to be a stroke of luck, in the sense that the compound we wanted to form was not superconducting”

“Which is the compound where the mixed valency of the copper leads to the superconductive transition”

Bednorz, J. G. and Müller, K. A. (1986) ‘Z. Phys. B 64, 189.

La2CuO4

Orthorhombic to tetragonal phase transition. Ba/La ratio: 1= 0,03, 2= 0,06, 3= 0,07

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Susceptibility Measurement

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Wu, M. K., Ashburn, J. R., Torng, C. J., Hor, P. H., Meng, R. L., Goa, I..,Huang, Z. J., Wang, Y. Q., and Chu, C. W. (1987) Phys. Rev. Lett. 58. 908;

Hor, P. H., Gao, L., Meng, R. L., Huang, Z. J., Wang, Y. Q., Forster, K.,Vassilious, J., Chu, C. W., Wu, M. K., Ashburn, J. R., and Torng, C. J. (1987)

ibid., 91 1.

La3+ and Sr3+ same ionic radius

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Yttrium Barium Copper Oxides Cuprate

Questions??