Magnetic Transitions in a Doped Mott Insulator Filling Information Gap, Searching for New Phase

Transcription

1 Magnetic Transitions in a Doped Mott Insulator Filling Information Gap, Searching for New Phase Michael Aling Mechanical Engineering PI: Stephen Wilson Mentor: Julian Schmehr Materials Science

2 Materials Science: A Broad Field New materials create new technologies Electronic and Magnetic Structural Nanomaterials Biomaterials

3 Materials Science: A Broad Field New materials create new technologies Electronic and Magnetic Structural Nanomaterials Biomaterials

4 Materials Science: A Broad Field New materials create new technologies Electronic and Magnetic Structural Nanomaterials Biomaterials Semiconductors Superconductors Condensed Matter Physics

5 Materials Science: A Broad Field New materials create new technologies Electronic and Magnetic Structural Nanomaterials Biomaterials Semiconductors Superconductors Condensed Matter Physics

6 Materials Science: A Broad Field New materials create new technologies Electronic and Magnetic Structural Nanomaterials Biomaterials Semiconductors Superconductors Condensed Matter Physics Modern Computing Solid State Devices Next-Gen Electronics

7 Materials Science: A Broad Field New materials create new technologies Electronic and Magnetic Structural Nanomaterials Biomaterials Semiconductors Superconductors Condensed Matter Physics Modern Computing Solid State Devices Next-Gen Electronics solarcostguide.com

8 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 1 mm Crystals of Sr 3 (Ir 1-x Ru x ) 2 O 7

9 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Temperature (K) Ru Level (%)

10 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Temperature (K) Insulator Metal Ru Level (%)

11 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Paramagnetic Temperature (K) 3 Anti- Ferromagnetic Ru Level (%)

12 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru Paramagnetic: disordered 300 Paramagnetic Temperature (K) Antiferromagnetic: ordered 3 Anti- Ferromagnetic Ru Level (%)

13 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 PM Temperature (K) Ins. Met. AF Ru Level (%)

14 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Temperature (K) Ru Level (%) Adapted from Dhital, et. al., 2014

15 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Metal Temperature (K) Insulator Metal Insulator Ru Level (%) Cross-section of a crystal near x=0.35 (schematic) Adapted from Dhital, et. al., 2014

16 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Paramagnetic (PM) Temperature (K) AF 3 Anti- Ferromagnetic Ru Level (%) Cross-section of a crystal near x=0.35 (schematic) Adapted from Dhital, et. al., 2014

17 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru Proximity makes metal AF as well 300 Paramagnetic (PM) Temperature (K) AF 3 Anti- Ferromagnetic Ru Level (%) Cross-section of a crystal near x=0.35 (schematic) Adapted from Dhital, et. al., 2014

18 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Temperature (K) AF PM Ru Level (%)

19 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru Temperature (K) 300 AF? PM Enhancement: caused by increasing interaction between AF and PM regions? Ru Level (%)

20 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Temperature (K) AF PM Ru Level (%)

21 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru 300 Temperature (K) AF PM Ru Level (%)?

22 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru Temperature (K) 300 AF PM Could be Another magnetic phase Other interesting phases Superconducting? Ru Level (%)?

23 Looking For a New Electronic Phase: Doping Sr 3 Ir 2 O 7 with Ru Temperature (K) 300 AF PM Goal: Develop understanding of both AF phase and the phase diagram Ru Level (%)

24 Characterization Necessitates Multiple Steps Recreate Prior Dopant Level (33%) Grow New Dopant Levels (40-60%) Perform Measurements Map and Characterize New Phase

25 Characterization Necessitates Multiple Steps Recreate Prior Dopant Level (33%) Grow New Dopant Levels (40-60%) Seven-Day Growth & Verifying Purity Perform Measurements Resistivity Magnetization Heat capacity Map and Characterize New Phase

26 Uncertainty Exists in Growth Process Dopant Level Varies Significantly, Even Among Best Samples

27 Uncertainty Exists in Growth Process Dopant Level Varies Significantly, Even Among Best Samples

28 Purity Estimation by Lattice Parameter: Reducing Costly EDX Tests Iridium/Ruthenium (at center) C Oxygen (red) Strontium Adapted from Jasongoh - Material studio, CC BY-SA 3.0,

29 Purity Estimation by Lattice Parameter: Reducing Costly EDX Tests Iridium/Ruthenium (at center) C Oxygen (red) Strontium Adapted from Jasongoh - Material studio, CC BY-SA 3.0,

30 Purity Estimation by Lattice Parameter: Reducing Costly EDX Tests Iridium/Ruthenium (at center) C Oxygen (red) Strontium Adapted from Jasongoh - Material studio, CC BY-SA 3.0,

31 Purity Estimation by Lattice Parameter: Reducing Costly EDX Tests Iridium/Ruthenium (at center) C Oxygen (red) Strontium Adapted from Jasongoh - Material studio, CC BY-SA 3.0,

32 Resistivity Quickly Reveals Features: Next step after obtaining pure samples

33 Resistivity Quickly Reveals Features: Next step after obtaining pure samples I V

34 Resistivity Quickly Reveals Features: Next step after obtaining pure samples I V

35 Resistivity Quickly Reveals Features: Next step after obtaining pure samples I V 1.5mm

36 Resistivity Quickly Reveals Features: Next step after obtaining pure samples Resistivity vs. Temperature (Representative, 34% Ru)

37 Resistivity Quickly Reveals Features: Next step after obtaining pure samples Resistivity vs. Temperature (Representative, 34% Ru) Insulating Metallic

38 Resistivity Quickly Reveals Features: Next step after obtaining pure samples Resistivity vs. Temperature (Representative, 34% Ru)

39 Resistivity Quickly Reveals Features: Next step after obtaining pure samples Resistivity vs. Temperature (Representative, 34% Ru)

40 Preliminary Progress on Phase Diagram Expansion Measurements Currently Limited to Resistivity Adapted from Dhital, et. al., 2014

41 Preliminary Progress on Phase Diagram Expansion Measurements Currently Limited to Resistivity Metal-insulator Magnetic No transitions observed at x=0.62

42 Future Work The roadmap continues this year Goal: Complete the phase diagram and study the antiferromagnetic metal

43 Future Work The roadmap continues this year Goal: Complete the phase diagram and study the antiferromagnetic metal Already achieved: Multiple dopant levels grown, with little contamination Samples sent to collaborators in Korea (x=0.33) Several successful resistivity runs Lattice parameter measurements Data so far agrees with previous analysis

44 Future Work The roadmap continues this year Goal: Complete the phase diagram and study the antiferromagnetic metal Already achieved: Multiple dopant levels grown, with little contamination Samples sent to collaborators in Korea (x=0.33) Several successful resistivity runs Lattice parameter measurements Data so far agrees with previous analysis Ready to move forward: More growths with 50-70% Ru (x=0.5 to 0.7) More resistivity runs on current and future samples Magnetization and heat capacity measurements Sub-Kelvin resistivity measurements

45 Acknowledgements References 1. Dhital, C. et al. Carrier localization and electronic phase separation in a doped spin-orbit-driven Mott phase in Sr 3 (Ir 1-x Ru x ) 2 O 7. Nat. Commun. 5:3377 doi: /ncomms4377 (2014). 2. Dhital, C. et al. Spin ordering and electronic texture in the bilayer iridate Sr 3 (Ir 1-x Ru x ) 2 O 7. Physical Review B 86, (R) (2012). 3. Jesche, A. et al. X-Ray diffraction on large single crystals using a powder diffractometer. Philosophical Magazine (2016).

46 Supplemental Slides

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48 x = 0 x = 0.34 Two samples peaks differing at the (00L)-type peak 0010 Modified Bragg s Law: 2 c sin Θ H R cos Θ = L λ Offset

49 Dhital, et. al., 2014

50 Resistivity Dhital, et. al., 2014

51 STS Measurements Insulating Metallic Dhital, et. al., 2014