Experimental band structure of potassium as measured by angle-resolved photoemission
- Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (USA)
The bulk band structure of potassium along the (110) direction was measured using angle-resolved photoemission from an epitaxial potassium film several thousand angstroms thick grown on a Ni(100) substrate. We find the occupied bandwidth to be 1.60{plus minus}0.05 eV, which is narrower than the free-electron bandwidth of 2.12 eV and agrees with recent calculations of the quasiparticle self-energy. A narrow peak near the Fermi level which did not disperse with photon energy was observed for photon energies which, according to the nearly-free-electron model, should yield no direct transitions. A comparison of the binding energy and intensity of the anomalous peak as functions of photon energy is made to the calculations of Shung and Mahan (Phys. Rev. B 38, 3856 (1988)). The discrepancies found are discussed in terms of an enhanced surface photoeffect in the photon energy range 20{le}{h bar}{omega}{le}30 eV. For low photon energies, a bulk peak was also observed due to a surface umklapp process with an intensity comparable to the standard bulk (110) peak. The possible contributions to this strong surface umklapp process from a shear instability at the first few (110) atomic planes is discussed.
- OSTI ID:
- 6949936
- Journal Information:
- Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:12; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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