SRC Users' Meeting - Synchrotron Radiation Center - University of ...
SRC Users' Meeting - Synchrotron Radiation Center - University of ... SRC Users' Meeting - Synchrotron Radiation Center - University of ...
[4] G. –H. Gweon, J. W. Allen, and J. D. Denlinger, cond-mat/0303122. [5] Mallet et al, Phys. Rev. B 63, 165428 (2001). k (Å -1 ) 0 y 0.2 0.4 A B Z Γ Q CDW1 M Y -0.5 0 0.5 k x (Å -1 ) Figure 1. Normal state Fermi energy intensitiy map of η-Mo4O11. White arrow shows the nesting vector for T=109K CDW transition. Intensity (arb. units) (a) 110 K 50 K -0.2 -0.1 0 0.1 (b) -0.2 -0.1 0 0.1 E-E F (eV) -1 -0.5 0 E-E F Figure 3. “Melted holon” lineshape at the Y point of the k-space. Figure 2. Temperature dependent change of the valence band spectrum at point A and B respectively.
THE FERMI SURFACES OF THIN Sb(111) FILMS Hartmut Höchst and Christian R. Ast Synchrotron Radiation Center, University of Wisconsin-Madison 3731 Schneider Drive, Stoughton, WI, 53589 The unique electronic properties of the group-V elements Sb and Bi, their small Fermi energy combined with highly anisotropic electron and hole masses and carrier concentrations several orders of magnitude lower than in normal metals makes them prime candidates for potential thermoelectric converters. Devices based on nano-scale structures of Sb and Bi or alloys thereof are among those with the highest conversion efficiency.[1,2] The rhombohedral (A7) crystal structure of the group V-elements causes a negative band gap. The conduction band minimum at the L-point is lower than the valence band maxima, which occur at the H-point for Sb and at the T-point for Bi. As a result, the Fermi surfaces (FS) consist of six pockets centered at the H-points or of two half-pockets centered at the T-points. Band structure calculations using different theoretical approaches agree in some basic overall Fermi surface features.[3-6].The calculated dimensions of the Fermi surface however have been far from experimental results based on magnetotransport and resonance measurements. These data were historically the most accurate even though indirect sources to judge the quality of the various theoretical approaches. More recently, photoemission spectroscopy (PES) was recognized to be a potentially useful additional tool to investigate the electronic properties near the FS. Compared to the classical FS measurements, PES has the advantage that information can be gathered from very small samples, at elevated temperatures and from materials, which exhibit strong impurity, compositional or structurally related scattering effects otherwise detrimental to most classical resonance based FS measurements. We report the first photoemission based FS data of Sb. Combining ARPES with the tuneability of synchrotron radiation allows determining the parallel components of the Fermi momentum k x and k y . Using a simple final state model provides also access to the perpendicular component k enables us to separate the three dimensional hole- pocket typical for bulk Sb from additional FS features which are of 2D-nature and most likely related to the presence of a Sb bilayer on the (111)-surface. Compared to Bi[7-9], which has extremely small bulk hole-pockets, preventing a detailed k-mapping due to experimental limitations in the momentum resolution, the carrier concentration in Sb is ~200 times larger and thus opening up the possibility of tracing the contours of the bulk hole-FS. The location and cross section of the hole pocket in the mirror plane compares well with theoretical predictions based upon pseudopotential calculations by Falicov and Lin [3] while other more recent and advanced model calculations [4-6] seem not to comply with our data. Acknowledgements The Synchrotron Radiation Center (SRC) is funded by the National Science Foundation (NSF) under Grant No. DMR-0884402.
- Page 2 and 3: Welcome to the 36 th SRC Users’ M
- Page 4 and 5: 12:20 - 1:10 Lunch 1:10 -1:45 Poste
- Page 6 and 7: Administration Executive Director D
- Page 8 and 9: STATUS OF THE SRC BEAMLINES AND INS
- Page 10 and 11: ACCELERATOR DEVELOPMENTS Ken Jacobs
- Page 12 and 13: HIGH ENERGY RESEARCH POSSIBILITIES
- Page 14 and 15: ATOMICALLY UNIFORM THIN FILMS ON SI
- Page 16 and 17: calculated binding energies of the
- Page 18 and 19: MANY-ELECTRON EFFECTS ON THE XE 5S
- Page 20 and 21: PHOTOELECTRON SPECTROMETRY OF ATOMI
- Page 22 and 23: PHOTOEMISSION STUDY OF USb AND UTe
- Page 24 and 25: CANADIAN SYNCHROTRON RADIATION FACI
- Page 26 and 27: SELF-ASSEMBLY OF BLOCK COPOLYMERS O
- Page 28 and 29: A B S T R A C T S
- Page 30 and 31: Photoemission spectra, a.u. -0.3 -0
- Page 32 and 33: THE INITIAL AND FINAL STATE BANDS I
- Page 34 and 35: TRANSITION LAYERS AT BURIED FERROMA
- Page 36 and 37: LOW-DIMENSIONAL ELECTRONS AT SILICO
- Page 38 and 39: SUBCELLULAR DISTRIBUTION OF MOTEXAF
- Page 40 and 41: LINEAR POLARIZATION MEASUREMENTS OF
- Page 42 and 43: Fig.1: Photoemission spectra of opt
- Page 44 and 45: The sample manipulator has a cool d
- Page 46 and 47: Cr and Fe but for these U systems t
- Page 50 and 51: References [1] S. Cho, Y. Kim, A. D
- Page 52 and 53: [3] D. L. Mills, Physical Review B
- Page 54 and 55: CHARACTERIZATION OF SULPHATE INTERA
- Page 56 and 57: in the data acquisition chamber. Th
- Page 58 and 59: spatially resolved chemistry of the
- Page 60 and 61: THE RELATIONSHIP BETWEEN PHOSPHATE
- Page 62 and 63: PHOTOEMISSION STUDIES OF QUANTUM WE
- Page 64 and 65: Ag surface state such that it moves
- Page 66 and 67: HIGH-RESOLUTION STUDY OF THE LITHIU
- Page 68 and 69: RELATIVE PARTIAL CROSS SECTIONS AND
- Page 70 and 71: Christian Ast Max-Planck Institute
- Page 72 and 73: David L. Huber Physical Sciences La
- Page 74 and 75: Tom Miller University of Illinois a
- Page 76 and 77: Eric Wiedemann University of Wiscon
- Page 78 and 79: Pete Hagen Phone: (608) 877-2154 Em
- Page 80: NOTES
[4] G. –H. Gweon, J. W. Allen, and J. D. Denlinger, cond-mat/0303122.<br />
[5] Mallet et al, Phys. Rev. B 63, 165428 (2001).<br />
k (Å -1 )<br />
0 y 0.2 0.4<br />
A<br />
B<br />
Z<br />
Γ<br />
Q CDW1<br />
M<br />
Y<br />
-0.5 0 0.5<br />
k x (Å -1 )<br />
Figure 1. Normal state Fermi energy<br />
intensitiy map <strong>of</strong> η-Mo4O11. White arrow<br />
shows the nesting vector for T=109K CDW<br />
transition.<br />
Intensity (arb. units)<br />
(a)<br />
110 K<br />
50 K<br />
-0.2 -0.1 0 0.1<br />
(b)<br />
-0.2 -0.1 0 0.1<br />
E-E F (eV)<br />
-1 -0.5 0<br />
E-E F<br />
Figure 3. “Melted holon”<br />
lineshape at the Y point <strong>of</strong> the<br />
k-space.<br />
Figure 2. Temperature dependent<br />
change <strong>of</strong> the valence band spectrum at<br />
point A and B respectively.
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