Evidence for topological band inversion of the phase change material Ge2Sb2Te5

Pauly, Christian; Liebmann, Marcus; Giussani, Alessandro; Kellner, Jens; Just, Sven; Sánchez-Barriga, Jaime; Rienks, Emile; Rader, Oliver; Calarco, Raffaella; Bihlmayer, Gustav; Morgenstern, Markus
December 2013
Applied Physics Letters;12/9/2013, Vol. 103 Issue 24, p243109
Academic Journal
We present an angle-resolved photoemission study of a ternary phase change material, namely Ge2Sb2Te5, epitaxially grown on Si(111) in the metastable cubic phase. The observed upper bulk valence band shows a minimum at [formula] being 0.3 eV below the Fermi level EF and a circular Fermi contour around [formula] with a dispersing diameter of 0.27-0.36 Å-1. This is in agreement with density functional theory calculations of the Petrov stacking sequence in the cubic phase which exhibits a topological surface state. The topologically trivial cubic Kooi-De Hosson stacking shows a valence band maximum at Γ in line with all previous calculations of the hexagonal stable phase exhibiting the valence band maximum at Γ for a trivial Z2 topological invariant ν0 and away from Γ for non-trivial ν0. Scanning tunneling spectroscopy exhibits a band gap of 0.4 eV around EF.


Related Articles

  • Postgrowth annealing of (Ga,Mn) As under As capping: An alternative way to increase TC. Adell, M.; Ilver, L.; Kanski, J.; Stanciu, V.; Svedlindh, P.; Sadowski, J.; Domagala, J. Z.; Terki, F.; Hernandez, C.; Charar, S. // Applied Physics Letters;3/14/2005, Vol. 86 Issue 11, p112501 

    In situ postgrowth annealing of (Ga,Mn)As layers under As capping is adequate for achieving high Curie temperatures (TC) in a similar way as ex situ annealing in air or in N2 atmosphere practiced earlier. Thus, the first efforts give an increase of TC from 68 to 145 K after 2 h annealing at 180...

  • Magnetic domain walls in T-shaped permalloy microstructures. Haug, T.; Back, C. H.; Raabe, J.; Heun, S.; Locatelli, A. // Applied Physics Letters;4/11/2005, Vol. 86 Issue 15, p152503 

    The magnetic domain wall width of T-shaped permalloy structures has been measured using a photoemission electron microscope and x-ray magnetic dichroism. The results are compared to micromagnetic simulations. The shape of the structures allows us to analyze 90° Néel walls. We find a...

  • Organic Schottky barrier photovoltaic cells based on MoOx/C60. Minlu Zhang; Huanjun Ding; Yongli Gao; Tang, C. W. // Applied Physics Letters;5/3/2010, Vol. 96 Issue 18, p183301 

    We report that the performance of indium tin oxide/molybdenum oxide/fullerene (ITO/MoOx/C60) photovoltaic cells is highly sensitive to the method of depositing MoOx film. The highest open-circuit voltage and short-circuit current are obtained using thermally evaporated MoOx. In contrast,...

  • Full characterization and optimization of a femtosecond ultraviolet laser source for time and angle-resolved photoemission on solid surfaces. Faure, J.; Mauchain, J.; Papalazarou, E.; Yan, W.; Pinon, J.; Marsi, M.; Perfetti, L. // Review of Scientific Instruments;Apr2012, Vol. 83 Issue 4, p043109 

    A novel experimental apparatus for time and angle-resolved photoemission on solid surfaces is presented. A 6.28 eV laser source operating at 250 kHz repetition rate is obtained by frequency mixing in nonlinear beta barium borate crystals. This UV light source has a high photon flux of 1013...

  • photoelectric effect.  // Hutchinson Dictionary of Scientific Biography;2005, p1 

    Transfer of energy from light rays falling onto a substance to the electrons within the substance. If the frequency, and hence the energy, of the radiation is high enough, it is possible to "boil" electrons, then known as photoelectrons, out of the substance. Being charge-carriers, these...

  • Intervalley scattering in MoS2 imaged by two-photon photoemission with a high-harmonic probe. Wallauer, R.; Reimann, J.; Armbrust, N.; Güdde, J.; Höfer, U. // Applied Physics Letters;10/172016, Vol. 109 Issue 16, p1 

    We report on the direct mapping of electron transfer in the momentum space of bulk MoS2 by means of time- and angle-resolved two-photon photoemission with a high-harmonic probe. For this purpose, we have combined a high-repetition rate high-harmonic source with tunable femtosecond pump pulses...

  • Structure and photoelectric properties of SiSn epilayers. Saidov, A. S.; Usmonov, Sh. N.; Kalanov, M.; Madaminov, Kh. M. // Technical Physics Letters;Sep2010, Vol. 36 Issue 9, p827 

    Epitaxial layers of n-type SiSn x (0 ≤ x ≤ 0.04) solid solution were grown by liquid phase epitaxy from tin-based solution melt confined between two horizontal Si(111) single crystal silicon substrates. The structure of epilayers was determined and the photosensitivity spectra of...

  • Strong luminescence from dislocation-free GaN nanopillars. Inoue, Y.; Hoshino, T.; Takeda, S.; Ishino, K.; Ishida, A.; Fujiyasu, H.; Kominami, H.; Mimura, H.; Nakanishi, Y.; Sakakibara, S. // Applied Physics Letters;9/20/2004, Vol. 85 Issue 12, p2340 

    GaN nanostructures were prepared on Si(111) by a hot-wall epitaxy technique employing the modified two-step growth method. Isolated hexagonal pillar-like GaN nanostructures (GaN nanopillars) with the typical diameter, height, and density of 200–300 nm, 0.5–1 μm, and 3–4...

  • Optical and electrical properties of (1-101)GaN grown on a 7° off-axis (001)Si substrate. Hikosata, T.; Narita, T.; Honda, Y.; Yamaguchi, M.; Sawaki, N. // Applied Physics Letters;6/7/2004, Vol. 84 Issue 23, p4717 

    Uniform growth of (1-101)GaN was performed on coalesced stripes of GaN which had been prepared by selective metalorganic vapor phase epitaxy on a 7° off-axis (001)Si substrate via an AlN intermediate layer. The cathodoluminescence spectra at 4 K exhibited a donor bound excitonic emission at...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics