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Title: Disorder-induced anomalously signed Hall effect in crystalline GeTe/Sb{sub 2}Te{sub 3} superlattice-like materials

Opposite to the almost persistent p-type conductivity of the crystalline chalcogenides along the GeTe-Sb{sub 2}Te{sub 3} tie line, n-type Hall mobility is observed in crystalline GeTe/Sb{sub 2}Te{sub 3} superlattice-like material (SLL) with a short period length. We suggest that this unusual carrier characteristic originates from the structural disorder introduced by the lattice strain and dangling bonds at the SLL interfaces, which makes the crystalline SLLs behave like the amorphous chalcogenides. Detailed structural disorder in crystalline SLL has been studied by Raman scattering, X-ray photoelectron spectroscopy, as well as Variable-energy positron annihilation spectroscopy measurements. First-principles calculations results show that this structural disorder gives rise to three-site junctions that dominate the charge transport as the period length decreases and result in the anomalously signed Hall effect in the crystalline SLL. Our findings indicate a similar tetrahedral structure in the amorphous and crystalline states of SLLs, which can significantly reduce the entropy difference. Due to the reduced entropy loss and increased resistivity of crystalline phase introduced by disorder, it is not surprising that the SLLs exhibit extremely lower RESET current and power consumption.
Authors:
; ; ; ;  [1] ;  [2]
  1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22494776
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 7; Other Information: (c) 2015 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; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANTIMONY TELLURIDES; CHARGE TRANSPORT; CRYSTALS; ENTROPY; GERMANIUM TELLURIDES; HALL EFFECT; N-TYPE CONDUCTORS; POSITRONS; RAMAN EFFECT; SEMICONDUCTOR JUNCTIONS; SUPERLATTICES; X-RAY PHOTOELECTRON SPECTROSCOPY