Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

From local structure to nanosecond recrystallization dynamics in AgInSbTe phase-change materials


Phase-change optical memories are based on the astonishingly rapid nanosecond-scale crystallization of nanosized amorphous ‘marks’ in a polycrystalline layer. Models of crystallization exist for the commercially used phase-change alloy Ge2Sb2Te5 (GST), but not for the equally important class of Sb–Te-based alloys. We have combined X-ray diffraction, extended X-ray absorption fine structure and hard X-ray photoelectron spectroscopy experiments with density functional simulations to determine the crystalline and amorphous structures of Ag3.5In3.8Sb75.0Te17.7 (AIST) and how they differ from GST. The structure of amorphous (a-) AIST shows a range of atomic ring sizes, whereas a-GST shows mainly small rings and cavities. The local environment of Sb in both forms of AIST is a distorted 3+3 octahedron. These structures suggest a bond-interchange model, where a sequence of small displacements of Sb atoms accompanied by interchanges of short and long bonds is the origin of the rapid crystallization of a-AIST. It differs profoundly from crystallization in a-GST.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Phase diagram of PC materials and crystallization patterns.
Figure 2: HXRD data for AIST and GST, and atomic configurations of a-AIST and a-GST.
Figure 3: Valence-band spectra and bond-order distributions in c- and a-AIST.
Figure 4: PC mechanism of a-AIST.
Figure 5: Ring statistics and PC in a-AIST and a-GST.


  1. Meinders, E. R., Mijiritskii, A. V., van Pieterson, L. & Wuttig, M. Optical Data Storage Vol. 4 (Philips Research Book Series, Springer, 2006).

    Google Scholar 

  2. Yamada, N., Ohno, E., Nishiuchi, K., Akahira, N. & Takao, M. Rapid phase transitions of GeTe–Sb2Te3 pseudobinary amorphous thin films for an optical disk memory. J. Appl. Phys. 69, 2849–2856 (1991).

    CAS  Article  Google Scholar 

  3. Matsunaga, T. & Yamada, N. Crystallographic studies on high-speed phase-change materials used for rewritable optical recording disks. Jpn J. Appl. Phys. 43, 4704–4712 (2004).

    CAS  Article  Google Scholar 

  4. Elliott, S. R. Physics of Amorphous Materials (Longman, 1984).

    Google Scholar 

  5. Lee, B-S. et al. Observation of the role of subcritical nuclei in crystallization of a glassy solid. Science 326, 980–984 (2009).

    CAS  Article  Google Scholar 

  6. Fukuyama, Y. et al. Time-resolved investigation of nanosecond crystal growth in rapid phase-change materials—correlation with the recording speed of digital versatile disc media. Appl. Phys. Exp. 1, 045001 (2008).

    Article  Google Scholar 

  7. Wuttig, M. & Yamada, N. Phase-change materials for rewriteable data storage. Nature Mater. 6, 824–832 (2007).

    CAS  Article  Google Scholar 

  8. Matsunaga, T., Umetani, Y. & Yamada, N. Structural study of a Ag3.4In3.7Sb76.4Te16.5 quadruple compound utilized for phase-change optical disks. Phys. Rev. B 64, 184116 (2001).

    Article  Google Scholar 

  9. Akola, J. et al. Experimentally constrained density functional calculations of the amorphous structure of the prototypical phase-change material Ge2Sb2Te5 . Phys. Rev. B 80, 020201(R) (2009).

    Article  Google Scholar 

  10. Kohara, S. et al. Structural basis for the fast phase change of Ge2Sb2Te5: Ring statistics analogy between the crystal and amorphous states. Appl. Phys. Lett. 89, 201910 (2006).

    Article  Google Scholar 

  11. Lee, M. L., Shi, L. P., Tian, Y. T., Gan, C. L. & Miao, X. S. Crystallization behavior of Sb70Te30 and Ag3In5Sb60Te32 chalcogenide materials for optical media applications. Phys. Status Solidi a 205, 340–344 (2008).

    CAS  Article  Google Scholar 

  12. Akola, J. & Jones, R. O. Structural phase transitions on the nanoscale: The crucial pattern in the phase change materials Ge2Sb2Te5 and GeTe. Phys. Rev. B 76, 235201 (2007).

    Article  Google Scholar 

  13. Akola, J. & Jones, R. O. Density functional study of amorphous, liquid, and crystalline Ge2Sb2Te5: Homopolar bonds and/or AB alternation? J. Phys. Condens. Matter 20, 365103 (2008).

    Article  Google Scholar 

  14. Tashiro, H. et al. Structural analysis of Ag–In–Sb–Te phase-change material. Jpn J. Appl. Phys. 41, 3758–3759 (2002).

    CAS  Article  Google Scholar 

  15. Kim, J-J. et al. Electronic structure of amorphous and crystalline (GeTe)1−x(Sb2Te3)x investigated using hard X-ray photoemission spectroscopy. Phys. Rev. B 76, 115124 (2007).

    Article  Google Scholar 

  16. Hoffmann, R. Solids and Surfaces: A Chemist’s View of Bonding in Extended Structures (Wiley-VCH, 1989).

    Google Scholar 

  17. Shportko, K. et al. Resonant bonding in crystalline phase-change materials. Nature Mater. 7, 653–658 (2008).

    CAS  Article  Google Scholar 

  18. Huang, B. & Robertson, J. Bonding origin of optical contrast in phase-change memory materials. Phys. Rev. B 81, 081204 (2010).

    Article  Google Scholar 

  19. Gronert, S. Gas phase studies of the competition between substitution and elimination reactions. Acc. Chem. Res. 36, 848–857 (2003).

    CAS  Article  Google Scholar 

  20. Mikosch, J. et al. Imaging nucleophilic substitution dynamics. Science 319, 183–186 (2008).

    CAS  Article  Google Scholar 

  21. Binnemans, K. Ionic liquid crystals. Chem. Rev. 105, 4148–4204 (2005).

    CAS  Article  Google Scholar 

  22. Njoroge, W. K. & Wuttig, M. Crystallization kinetics of sputter-deposited amorphous AgInSbTe films. J. Appl. Phys. 90, 3816–3821 (2001).

    CAS  Article  Google Scholar 

  23. Shakhvorostov, D. et al. Evidence of electronic gap-driven metal–semiconductor transition in phase change materials. Proc. Natl Acad. Sci. USA 106, 10907–10911 (2009).

    CAS  Article  Google Scholar 

  24. Cooper, A. R. Zachariasen’s rules, Madelung constant, and network topology. Phys. Chem. Glasses 19, 60–68 (1978).

    CAS  Google Scholar 

  25. Ziman, J. M. Models of Disorder (Cambridge Univ. Press, 1979).

    Google Scholar 

  26. Her, U-C., Chen, H. & Hsu, Y-S. Effects of Ag and In addition on the optical properties and crystallization kinetics of eutectic Sb70Te30 phase-change recording film. J. Appl. Phys. 93, 10097–10103 (2003).

    CAS  Article  Google Scholar 

  27. Caravati, S., Bernasconi, M., Kühne, T. D., Krack, M. & Parrinello, M. Coexistence of tetrahedral- and octahedral-like sites in amorphous phase change materials. Appl. Phys. Lett. 89, 171906 (2007).

    Article  Google Scholar 

  28. Hegedüs, J. & Elliott, S. R. Microscopic origin of the fast crystallization ability of Ge–Sb–Te phase-change memory materials. Nature Mater. 7, 399–405 (2008).

    Article  Google Scholar 

  29. Kohara, S. et al. Structural studies of disordered materials using high-energy X-ray diffraction from ambient to extreme conditions. J. Phys. Condens. Matter 19, 506101 (2007).

    Article  Google Scholar 

  30. Ankudinov, A. L., Ravel, B., Rehr, J. J. & Conradson, S. D. Real-space multiple-scattering calculation and interpretation of X-ray-absorption near-edge structure. Phys. Rev. B 58, 7565–7576 (1998).

    CAS  Article  Google Scholar 

  31. Taguchi, T., Ozawa, T. & Yashiro, H. REX2000: Yet another XAFS analysis package. Phys. Scr. T115, 205–206 (2005).

    CAS  Article  Google Scholar 

  32. Kobayashi, K. et al. High resolution–high energy X-ray photoelectron spectroscopy using third-generation synchrotron radiation source, and its application to Si–high k insulator systems. Appl. Phys. Lett. 83, 1005–1007 (2003).

    CAS  Article  Google Scholar 

  33. Shirley, D. A. High-resolution X-ray photoemission spectrum of the valence bands of gold. Phys. Rev. B 5, 4709–4714 (1972).

    Article  Google Scholar 

  34. CPMD version 3.13. © IBM Corporation (1990–2009), © MPI für Festkörperforschung, Stuttgart (1997–2001).

  35. Perdew, J. P. et al. Restoring the density-gradient expansion for exchange in solids and surfaces. Phys. Rev. Lett. 100, 136406 (2008).

    Article  Google Scholar 

  36. Troullier, N. & Martins, J. L. Efficient pseudopotentials for plane-wave calculations. Phys. Rev. B 43, 1993–2006 (1991).

    CAS  Article  Google Scholar 

  37. Akola, J. & Jones, R. O. Structure of liquid phase change material AgInSbTe from density functional/molecular dynamics simulations. Appl. Phys. Lett. 94, 251905 (2009).

    Article  Google Scholar 

  38. Greben, O., Jóvári, P., Temleitner, L. & Pusztai, L. A new version of the RMC++ reverse Monte Carlo programme, aimed at investigating the structure of covalent glasses. J. Optoelectron. Adv. Mater. 9, 3021–3027 (2007).

    Google Scholar 

Download references


This work was supported by Core Research for Evolutional Science and Technology (CREST) ‘X-ray pinpoint structural measurement project—Development of the spatial- and time-resolved structural study for nano-materials and devices’ and by the Academy of Finland and the Japan Science and Technology Agency through the Strategic Japanese–Finnish Cooperative Program on ‘Functional materials’. The synchrotron radiation experiments were approved by the Japan Synchrotron Radiation Research Institute (proposal Nos 2007A1223, 2008A1409 and 2009A12386), and all calculations were carried out on the Jugene (IBM BlueGene/P) and Juropa (Xeon 5570) computers in the Forschungszentrum Jülich with grants from the John von Neumann Institute for Computing and the Forschungszentrum Jülich. We thank N. Yasuda and Y. Fukuyama for assistance in the density estimation measurement and H-P. Komsa for providing the initial 648-atom system coordinates for crystalline AIST.

Author information

Authors and Affiliations



The experiments/calculations were carried out and analysed as follows: sample preparation, R.K., T.M., N.Y.; high-energy XRD and RMC, S.K., M.T.; EXAFS, T.H., S.K., T.M.; XPS, E.I., K.K., T.M.; DF-MD, J.A., R.O.J. The manuscript was planned by J.A., R.O.J., S.K., T.M. and N.Y. and written by R.O.J.

Corresponding author

Correspondence to Noboru Yamada.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplemntary Information (PDF 870 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Matsunaga, T., Akola, J., Kohara, S. et al. From local structure to nanosecond recrystallization dynamics in AgInSbTe phase-change materials. Nature Mater 10, 129–134 (2011).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

Further reading


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing