scholarly journals Understanding the fast phase-change mechanism of tetrahedrally bonded Cu2GeTe3 : Comprehensive analyses of electronic structure and transport phenomena

2018 ◽  
Vol 97 (19) ◽  
Author(s):  
Keisuke Kobayashi ◽  
Jonathan M. Skelton ◽  
Yuta Saito ◽  
Satoshi Shindo ◽  
Masaaki Kobata ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Phase Change ◽  
Transport Phenomena ◽  
Change Mechanism ◽  
Fast Phase ◽  
Tetrahedrally Bonded

Phase Change in (GeTe)1-x(Sb2Te3)x Investigated by Hard X-ray Photoemission Spectroscopy

2008 ◽  
Vol 1072 ◽  
Author(s):  
Keisuke Kobayashi ◽  
Jung-Jin Kim ◽  
Toshiyuki Matsunaga ◽  
Kouichi Kifune ◽  
Eiji Ikenaga ◽  
...  
Keyword(s):  
Phase Change ◽  
Essential Role ◽  
Close Relation ◽  
Photoemission Spectroscopy ◽  
Crystalline Phases ◽  
X Ray ◽  
Change Mechanism ◽  
Fast Phase ◽  
Similar Chemical ◽  
Valence Electrons

ABSTRACTThe mechanism of the fast reversible change between the amorphous and crystalline phases in (GeTe)1−x(Sb2Te3)x (GST) has not yet been fully understood. The crystalline phase has been identified as having a NaCl-type cubic structure with random occupation of the A sites by Ge, Sb and vacancies, and 100% occupation of B sites by Te. This fact calls our attention to a possible close relation to the inherent crystal bonding instability observed for the average five valence electrons (<5>) family. We present here the results of systematic hard X-ray photoemission experiments on GST films with various compositions in both the amorphous and crystalline phases, and discuss that a similar chemical bonding instability does indeed play an essential role in the phase change mechanism in GST. We propose a model for the fast phase change, in which 6 fold to 3 fold transition of p-like bonding play an essential role, in this class of materials.

Characterization of Ultra-Fast Phase Change Optical Disk with GaSb Material

2003 ◽  
Vol 803 ◽  
Author(s):  
Kazunori Ito ◽  
Hiroko Tashiro ◽  
Makoto Harigaya ◽  
Eiko Suzuki ◽  
Katsuhiko Tani ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Melting Point ◽  
Phase Change ◽  
Crystal Growth Rate ◽  
Crystallization Mechanism ◽  
Fast Phase ◽  
Optical Disks ◽  
Digital Versatile Disk

ABSTRACTWe studied the crystallization mechanism of ultra-fast phase change optical disks with recording layers made of GaSb material for digital versatile disk (DVD) systems. The results of a static recording test and an amorphous mark formation simulation suggest that GaSb maintains a high crystal growth rate even at temperatures 150 degrees lower than the material's melting point. Disks with recording layers made of this material have a write speed margin ranging from DVD 3× to 8× or more.

scholarly journals Simultaneously high thermal stability and ultra-fast phase change speed based on samarium-doped antimony thin films

RSC Advances ◽  
2017 ◽  
Vol 7 (49) ◽  
pp. 31110-31114 ◽  
Author(s):  
Hua Zou ◽  
Yifeng Hu ◽  
Xiaoqin Zhu ◽  
Zhitang Song
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
Phase Change ◽  
High Thermal Stability ◽  
Trade Off ◽  
Fast Phase ◽  
Crystallization Speed

In general, there is trade-off between the crystallization speed and the thermal stability. Here, the Sm–Sb materials simultaneously realize high thermal stability and the ultrafast phase change speed by Sm doping.

Exploring the limits of fast phase change materials

2001 ◽  
Vol 674 ◽  
Author(s):  
Han-Willem Wöltgens ◽  
Ralf Detemple ◽  
Inés Friedrich ◽  
Walter K. Njoroge ◽  
Ingo Thomas ◽  
...  
Keyword(s):  
Activation Energy ◽  
Phase Change ◽  
Phase Change Materials ◽  
Ternary Alloys ◽  
Electrical Measurements ◽  
Material Synthesis ◽  
Fast Phase ◽  
Chalcogenide Alloys ◽  
Speed Up ◽  
Critical Nuclei

ABSTRACTIn the last decade a number of chalcogenide alloys, including ternary alloys of GeSbTe and quaternary alloys of InAgSbTe, have been identified which enable fast phase change recording. In the quest for materials with improved phase change kinetics we present two different approaches. By comparing alloys with well-defined stoichiometries the mechanisms which govern the transformation kinetics are determined. Optical and electrical measurements determine the activation energy for crystallization to 2.24 ± 0.11 eV for Ge2Sb2Te5 and to 3.71 ± 0.07 eV for Ge4Sb1Te5, respectively. It is shown that for GeSbTe-alloys with different composition the activation energy increases linearly with increasing Ge content. Power-time- reflectivity change diagrams recorded with a static tester reveal that Ge2Sb2Te5, in agreement with previous data, recrystallizes by the growth of sub critical nuclei, while Ge4Sb1Te5 grows from the crystalline rim surrounding the bit.To speed up the search for faster materials we employ concepts of combinatorial material synthesis by producing films with a stoichiometry gradient. Then laterally resolved secondary neutral mass spectroscopy (SNMS) combined with the static tester are used to identify the composition with superior properties for phase change applications.

Self-tracking planar concentrator using a solar actuated phase-change mechanism

2013 ◽  
Author(s):  
Eric J. Tremblay ◽  
Volker Zagolla ◽  
Damien Loterie ◽  
Christophe Moser
Keyword(s):  
Phase Change ◽  
Change Mechanism

Phase stability and electronic structure of Si2Sb2Te5 phase-change material

2010 ◽  
Vol 71 (8) ◽  
pp. 1165-1167 ◽  
Author(s):  
Baisheng Sa ◽  
Nahihua Miao ◽  
Jian Zhou ◽  
Zhitang Song ◽  
Zhimei Sun ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Stability ◽  
Change Material
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