1. Materials 286K seshadri@mrl.ucsb.edu Class 08. LnNiO 3 LaNiO 3 and LaCuO 3 are some of the few (undoped) metals.

2. Materials 286K seshadri@mrl.ucsb.edu Class 08. LnNiO 3 Strong lattice effects in the M–I transition of LnNiO 3 Torrance, Lacorre, Nazzal, Ansaldo, Niedermayer, Phys. Rev. B. 45 (1992) 8209–8212.

3. Materials 286K seshadri@mrl.ucsb.edu The transition is nicely tunable with average rare-earth size Class 08. LnNiO 3 Medarde et al., J. Phys. Condensed Matter 9 (1997) 1679.

4. Materials 286K seshadri@mrl.ucsb.edu Obradors et al. Phys. Rev. B 47 (1993) 12353. Pressure effects --- high pressures are like large A-cations Class 08. LnNiO 3

5. Materials 286K seshadri@mrl.ucsb.edu Medarde, Lacorre, Conder, Fauth, Furrer, Phys. Rev. Lett. 80 (1998) 2397–2400. Lattice dynamics is important: Strong isotope effect Class 08. LnNiO 3

6. Materials 286K seshadri@mrl.ucsb.edu Class 08. LnNiO 3 The room-temperature crystal structures Medarde et al., J. Phys. Condensed Matter 9 (1997) 1679.

7. Materials 286K seshadri@mrl.ucsb.edu Perovskite structures: Group-subgroup relations Class 08. LnNiO 3 from James Rondinelli, Northwestern.

8. Materials 286K seshadri@mrl.ucsb.edu The complete phase diagram orthorhombic monoclinic Class 08. LnNiO 3 from James Rondinelli, Northwestern.

9. Materials 286K seshadri@mrl.ucsb.edu Monoclinic phase Class 08. LnNiO 3 from James Rondinelli, Northwestern.

10. Materials 286K seshadri@mrl.ucsb.edu Decomposing the monoclinic structure into into its irreducible representations: = Class 08. LnNiO 3 from James Rondinelli, Northwestern.

11. Materials 286K seshadri@mrl.ucsb.edu 11 T MI – metal-insulator transition correlates with rotations, breathing & bending of octahedra, while T N – AFM ordering transition correlates with first-order Jahn-Teller type of distortions Breathing distortion correlates with MIT Jahn-Teller distortion correlates with magnetism Balachandran, Rondinelli, Phys. Rev. B 88 (2013) 054101. Class 08. LnNiO 3

12. Materials 286K seshadri@mrl.ucsb.edu 12 First-order localized to delocalized transition in LaCoO 3 Raccah, Goodenough, Phys. Rev. 155 (1967) 932–943. Class 08. LnCoO 3

13. Materials 286K seshadri@mrl.ucsb.edu 13 First-order localized to delocalized transition in LaCoO 3 Raccah, Goodenough, Phys. Rev. 155 (1967) 932–943. Class 08. LnCoO 3

14. Materials 286K seshadri@mrl.ucsb.edu 14 First-order localized to delocalized transition in LaCoO 3 Raccah, Goodenough, Phys. Rev. 155 (1967) 932–943. Class 08. LnCoO 3

15. Materials 286K seshadri@mrl.ucsb.edu 15 More subtle structural effects (orbital ordering?): Maris, Ren, Volotchaev, Lorenz, Palstra, Phys. Rev. B. 67 (2003) 224423(1–5). Class 08. LnCoO 3

16. Materials 286K seshadri@mrl.ucsb.edu 16 M–I transition with temperature and hole doping (Sr substitution) Bhide, Rajoria, Rao, Rama Rao, Jadhao, Phys. Rev. B. 12 (1975) 2832–2843. Class 08. LnCoO 3

17. Materials 286K seshadri@mrl.ucsb.edu 17 La 0.5 Sr 0.5 CoO 3–  prepared under different annealing conditions Haggerty, Seshadri, J. Phys. Condensed Matter 16 (2004) 6477–6484. Class 08. LnCoO 3

18. Materials 286K seshadri@mrl.ucsb.edu 18 Haggerty, Seshadri, J. Phys. Condensed Matter 16 (2004) 6477–6484. Class 08. LnCoO 3 La 0.5 Sr 0.5 CoO 3–  prepared under different annealing conditions

19. Materials 286K seshadri@mrl.ucsb.edu 19 La 0.5 Sr 0.5 CoO 3 band structure. Majority and minority bands have very different bandwidths. Haggerty, Seshadri, J. Phys. Condensed Matter 16 (2004) 6477–6484. Class 08. LnCoO 3