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Title: Terahertz and direct current losses and the origin of non-Drude terahertz conductivity in the crystalline states of phase change materials

THz and DC losses in crystalline states of GeSbTe and AgInSbTe phase-change material systems are re-examined and discussed. Although a simple free carrier transport has been assumed so far in the GeSbTe (GST) system, it is shown through recent experimental results that a series sequence of intragrain and intergrain (tunneling) transport, as recently formulated in Shimakawa et al., “The origin of non-Drude terahertz conductivity in nanomaterials,” Appl. Phys. Lett. 100, 132102 (2012) may dominate the electronic transport in the commercially utilized GST system, producing a non-Drude THz conductivity. The extracted physical parameters such as the free-carrier density and mobility are significantly different from those obtained from the Drude law. These physical parameters are consistent with those obtained from the DC loss data, and provide further support for the model. Negative temperature coefficient of resistivity is found even in the metallic state, similar to amorphous metals, when the mean free path is short. It is shown that the concept of minimum metallic conductivity, often used in the metal-insulator transition, cannot be applied to electronic transport in these materials.
Authors:
 [1] ;  [2] ; ;  [1] ; ;  [3] ;  [4]
  1. Department of General and Inorganic Chemistry, University of Pardubice, Pardubice (Czech Republic)
  2. (Japan)
  3. Institute of Physics, Academy of Sciences of the Czech Republic, Prague (Czech Republic)
  4. Department of Electrical Engineering, University of Saskatchewan, Saskatoon SK S7N 5A9 (Canada)
Publication Date:
OSTI Identifier:
22266102
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 23; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; CARRIER DENSITY; CRYSTALS; DIRECT CURRENT; LOSSES; MEAN FREE PATH; METALS; MOBILITY; NANOSTRUCTURES; PHASE CHANGE MATERIALS; TEMPERATURE COEFFICIENT; TUNNEL EFFECT