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Band structure information from soft x-ray spectroscopy Andrew Preston

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Presentation on theme: "Band structure information from soft x-ray spectroscopy Andrew Preston"— Presentation transcript:

1 Band structure information from soft x-ray spectroscopy Andrew Preston andrew@preston.co.nz

2 Boston University Slideshow Title Goes Here Materials World Network 09/09/28 Spintronics group Ben Ruck, Joe Trodahl Electronic structure group Walter Lambrecht Novel Materials Lab Kevin Smith

3 Boston University Slideshow Title Goes Here Kevin Smith Louis Piper Sang Wan Cho Alex DeMasi NML at BU 09/09/28

4 Boston University Slideshow Title Goes Here NML at BU 09/09/28  Novel materials  Nitrides: Rare-earth nitrides, III-V  Oxides: TCO, SOFC, low dimensional  Organics  X-ray spectroscopy  Absorption (XAS)  Emission (XES)  Resonant emission (RXES, RIXS)  Photoemission (XPS)  Angle resolved photoemission (ARPES)

5 Boston University Slideshow Title Goes Here NML at BU 09/09/28  Synchrotron based  National Synchrotron Light Source – X1B  Advanced Light Source – BL7, BL12  MAXlab – 5II

6 Boston University Slideshow Title Goes Here Spectroscopy 09/09/28

7 Boston University Slideshow Title Goes Here Spectroscopy 09/09/28

8 Boston University Slideshow Title Goes Here X-ray absorption (XAS) EfEf Empty Filled 09/09/28

9 Boston University Slideshow Title Goes Here X-ray absorption (XAS) EfEf Empty Filled 09/09/28

10 Boston University Slideshow Title Goes Here Site selectivity 09/09/28

11 Boston University Slideshow Title Goes Here Typical XAS 09/09/28

12 Boston University Slideshow Title Goes Here XAS 09/09/28 Kotani, Shin Rev. Mod. Phys. 73, 203 (2001) Curtain!

13 Boston University Slideshow Title Goes Here ZnO XAS 09/09/28

14 Boston University Slideshow Title Goes Here Zinc oxide 09/09/28

15 Boston University Slideshow Title Goes Here Zinc oxide  Zn = [Ar]3d 10 4s 2 O = [He]2s 2 2p 4 09/09/28

16 Boston University Slideshow Title Goes Here ZnO electronic structure 09/09/28  Density functional theory  HSE03 XC functional  GW correction  Essential for correctly locating the Zn 3d electrons, bandgap

17 Boston University Slideshow Title Goes Here ZnO electronic structure 09/09/28

18 Boston University Slideshow Title Goes Here Zinc oxide 09/09/28

19 Boston University Slideshow Title Goes Here ZnO electronic structure 09/09/28

20 Boston University Slideshow Title Goes Here Dipole approximation  Orbital selection  Δl = ±1  s -> p 09/09/28

21 Boston University Slideshow Title Goes Here ZnO electronic structure 09/09/28

22 Boston University Slideshow Title Goes Here ZnO electronic structure 09/09/28

23 Boston University Slideshow Title Goes Here ZnO XAS 09/09/28

24 Boston University Slideshow Title Goes Here ZnO anisotropy 09/09/28

25 Boston University Slideshow Title Goes Here ZnO anisotropy ZnO crystal O p orbitals 09/09/28

26 Boston University Slideshow Title Goes Here Orbital selection 09/09/28

27 Boston University Slideshow Title Goes Here ZnO anisotropy 09/09/28

28 Boston University Slideshow Title Goes Here ZnO XAS 09/09/28

29 Boston University Slideshow Title Goes Here X-ray emission (XES) EfEf Empty Filled 09/09/28

30 Boston University Slideshow Title Goes Here XES 09/09/28 Kotani, Shin Rev. Mod. Phys. 73, 203 (2001) Curtain!

31 Boston University Slideshow Title Goes Here XES 09/09/28 Kotani, Shin Rev. Mod. Phys. 73, 203 (2001)

32 Boston University Slideshow Title Goes Here Dipole approximation  Orbital selection  Δl = ±1  p -> s 09/09/28

33 Boston University Slideshow Title Goes Here ZnO XAS and XES 09/09/28

34 Boston University Slideshow Title Goes Here ZnO XAS and XES 09/09/28

35 Boston University Slideshow Title Goes Here ZnO XAS and XES 09/09/28

36 Boston University Slideshow Title Goes Here XES anisotropy? 09/09/28

37 Boston University Slideshow Title Goes Here XES and XPS 09/09/28

38 Boston University Slideshow Title Goes Here XAS and XES  Optical processes (photon in/photon out)  Magnetic fields  Insulators  Dirty surfaces  Capping layers  Advantages over photoemission in some domains 09/09/28

39 Boston University Slideshow Title Goes Here Selection rules 09/09/28  Site selection  Orbital selection  Dipole selection rule (conservation of angular momentum)  Orbital selection 2  Linear polarization + crystalline anisotropy  Dispersion?

40 Boston University Slideshow Title Goes Here Resonant x-ray emission (RXES) EfEf Empty Filled 09/09/28

41 Boston University Slideshow Title Goes Here RXES  Kramers-Heisenberg  Coherent 2 nd order process  XAS from |i> to |m>, followed by XES from |m> to |f>  Selection rule: conservation of crystal momentum! 09/09/28

42 Boston University Slideshow Title Goes Here RXES = coherent and incoherent XES 09/09/28

43 Boston University Slideshow Title Goes Here RXES 09/09/28

44 Boston University Slideshow Title Goes Here RXES 09/09/28

45 Boston University Slideshow Title Goes Here RXES 09/09/28 Kotani, Shin Rev. Mod. Phys. 73, 203 (2001)

46 Boston University Slideshow Title Goes Here ZnO anisotropy 09/09/28

47 Boston University Slideshow Title Goes Here 09/09/28 ZnO RXES

48 Boston University Slideshow Title Goes Here 09/09/28 ZnO RXES

49 Boston University Slideshow Title Goes Here ZnO RXES 09/09/28

50 Boston University Slideshow Title Goes Here ZnO electronic structure 09/09/28

51 Boston University Slideshow Title Goes Here ZnO p xy band structure 09/09/28

52 Boston University Slideshow Title Goes Here 09/09/28 ZnO p z band structure

53 Boston University Slideshow Title Goes Here Phys. Rev. B 78, 155114 (2008)  XAS, XES, and RXES to measure orbital resolved electronic structure and band dispersion  B. J. Ruck  Victoria University of Wellington  L. F. J. Piper, A. DeMasi, K. E. Smith  Boston University  A. Schleife, F. Fuchs, F. Bechstedt  Friedrich-Schiller-Universitat  J. Chai, S. M. Durbin  Canterbury University 09/09/28

54 Boston University Slideshow Title Goes Here Can we calculate the RXES? andrew@preston.co.nz 09/09/28

55 Boston University Slideshow Title Goes Here X-ray photoemission (XPS) 09/09/28 EfEf Empty Filled

56 Boston University Slideshow Title Goes Here EfEf Empty Filled X-ray photoemission (XPS) 09/09/28

57 Boston University Slideshow Title Goes Here EfEf Empty Filled EfEf Angle resolved XPS (ARPES) 09/09/28

58 Boston University Slideshow Title Goes Here ZnO RXES 09/09/28

59 Boston University Slideshow Title Goes Here X-ray absorption (XAS) EfEf Empty Filled 09/09/28

60 Boston University Slideshow Title Goes Here X-ray emission (XES) Empty Filled 09/09/28

61 Boston University Slideshow Title Goes Here ZnO electronic structure  Quantum mechanics  Discrete states for energy eigenvalues  Crystalline material  Crystal momentum affects eigenvalues 09/09/28

62 Boston University Slideshow Title Goes Here Dipole approximation 09/09/28

63 Boston University Slideshow Title Goes Here Selection rules 09/09/28

64 Boston University Slideshow Title Goes Here ZnO electronic structure 09/09/28

65 Boston University Slideshow Title Goes Here Resonant XES 09/09/28


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