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Phonons in Epitaxial DySi2: From the Bulk to Self-Organized Nanoislands and Nanowires

Svetoslav Stankov1,2,*, Przemysław Piekarz3,†, Anja Seiler2, Dániel G. Merkel4, Olga Bauder2, Ramu Pradip2, Tilo G. Baumbach1,2, Aleksandr I. Chumakov5, and Rudolf Rüffer5

  • *Contact author: Svetoslav.Stankov@kit.edu
  • †Contact author: Przemyslaw.Piekarz@ifj.edu.pl
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Phys. Rev. Lett. 135, 256202 – Published 17 December, 2025

DOI: https://doi.org/10.1103/4r3t-tr77

Abstract

Using nuclear inelastic scattering on Dy161, we determined the Dy-partial phonon density of states of epitaxial DySi2 in bulk and self-organized nanoislands and nanowires (NWs) on vicinal Si(001) surface. Compared to the bulk, the nanoislands exhibit softening of the crystal lattice, which is further enhanced in the NWs and significantly affects their thermodynamic and elastic properties. Our ab initio calculations reveal that the origin of this effect is the vibrations of Dy atoms located at the surfaces of the nanoislands and the NWs as well as forming a (2×4) reconstruction on the Si(001) surface between the NWs. The results demonstrate that, opposite to the widely accepted anisotropic lattice mismatch model, the NWs form with their length along the [0001] direction of the strained hexagonal unit cell with lattice parameters close to the Si(001) surface.

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References (80)

  1. G. P. Srivastava, The Physics of Phonons, 1st ed. (CRC Press, Boca Raton, 1990).
  2. B. Fultz, Vibrational thermodynamics of materials, Prog. Mater. Sci. 55, 247 (2010).
  3. M. A. Stroscio and M. Dutta, Phonons in Nanostructures, 1st ed. (Cambridge University Press, Cambridge, England, 2001).
  4. S. Stankov, R. Röhlsberger, T. Ślęzak, M. Sladecek, B. Sepiol, G. Vogl, A. I. Chumakov, R. Rüffer, N. Spiridis, J. Łażewski, K. Parliński, and J. Korecki, Phonons in iron: From the bulk to an epitaxial monolayer, Phys. Rev. Lett. 99, 185501 (2007).
  5. T. Ślęzak, J. Łażewski, S. Stankov, K. Parlinski, R. Reitinger, M. Rennhofer, R. Rüffer, B. Sepiol, M. Ślęzak, N. Spiridis, M. Zając, A. I. Chumakov, and J. Korecki, Phonons at the Fe(110) surface, Phys. Rev. Lett. 99, 066103 (2007).
  6. B. Roldan Cuenya, W. Keune, R. Peters, E. Schuster, B. Sahoo, U. von Hörsten, W. Sturhahn, J. Zhao, T. S. Toellner, E. E. Alp, and S. D. Bader, High-energy phonon confinement in nanoscale metallic multilayers, Phys. Rev. B 77, 165410 (2008).
  7. A. Seiler, P. Piekarz, S. Ibrahimkutty, D. G. Merkel, O. Waller, R. Pradip, A. I. Chumakov, R. Rüffer, T. Baumbach, K. Parlinski, M. Fiederle, and S. Stankov, Anomalous lattice dynamics of EuSi2 nanoislands: Role of interfaces unveiled, Phys. Rev. Lett. 117, 276101 (2016).
  8. J. Kalt, M. Sternik, I. Sergueev, J. Herfort, B. Jenichen, H.-C. Wille, O. Sikora, P. Piekarz, K. Parlinski, T. Baumbach, and S. Stankov, Lattice dynamics of epitaxial strain-free interfaces, Phys. Rev. B 98, 121409(R) (2018).
  9. R. Pradip, P. Piekarz, D. G. Merkel, J. Kalt, O. Waller, A. I. Chumakov, R. Rüffer, A. M. Oleś, K. Parlinski, T. Baumbach, and S. Stankov, Phonon confinement and spin-phonon coupling in tensile-strained ultrathin EuO films, Nanoscale 11, 10968 (2019).
  10. S. Stankov, D. G. Merkel, J. Kalt, J. Göttlicher, J. Łażewski, M. Sternik, P. T. Jochym, P. Piekarz, T. Baumbach, A. I. Chumakov, and R. Rüffer, Phonon confinement and interface lattice dynamics of ultrathin high-k rare earth sesquioxide films: The case of Eu2O3 on YSZ(001), Nanoscale Adv. 4, 19 (2022).
  11. D. Bozyigit, N. Yazdani, M. Yarema, O. Yarema, W. M. M. Lin, S. Volk, K. Vuttivorakulchai, M. Luisier, F. Juranyi, and V. Wood, Soft surfaces of nanomaterials enable strong phonon interactions, Nature (London) 531, 618 (2016).
  12. C. Berk, M. Jaris, W. Yang, S. Dhuey, S. Cabrini, and H. Schmidt, Strongly coupled magnon–phonon dynamics in a single nanomagnet, Nat. Commun. 10, 2652 (2019).
  13. J. Chen, X. Xu, J. Zhou, and B. Li, Interfacial thermal resistance: Past, present, and future, Rev. Mod. Phys. 94, 025002 (2022).
  14. J. P. Pekola and B. Karimi, Colloquium: Quantum heat transport in condensed matter systems, Rev. Mod. Phys. 93, 041001 (2021).
  15. S. Bandyopadhyay, Introduction to Spintronics, 2nd ed. (CRC Press, Boca Raton, 2015).
  16. N. Li, J. Ren, L. Wang, G. Zhang, P. Hänggi, and B. Li, Colloquium: Phononics: Manipulating heat flow with electronic analogs and beyond, Rev. Mod. Phys. 84, 1045 (2012).
  17. A. A. Balandin and D. L. Nika, Phononics in low-dimensional materials, Mater. Today 15, 266 (2012).
  18. S. Volz et al., Nanophononics: State of the art and perspectives, Eur. Phys. J. B 89, 15 (2016).
  19. M. Jansen, W. A. Tisdale, and V. Wood, Nanocrystal phononics, Nat. Mater. 22, 161 (2023).
  20. CMOS Nanoelectronics Innovative Devices, Architectures, and Applications, edited by N. Collaert, 1st ed. (Jenny Stanford Publishing, Singapore, 2012).
  21. S. Bandyopadhyay, Physics of Nanostructured Solid State Devices, 1st ed. (Springer Science and Business Media, New York, 2012).
  22. J. Yao, H. Yan, S. Das, J. F. Klemic, J. C. Ellenbogen, and C. M. Lieber, Nanowire nanocomputer as a finite-state machine, Proc. Natl. Acad. Sci. U.S.A. 111, 2431 (2014).
  23. C. Preinesberger, S. Vandré, T. Kalka, and M. Dähne-Prietsch, Formation of dysprosium silicide wires on Si(001), J. Phys. D 31, L43 (1998).
  24. Y. Chen, D. A. A. Ohlberg, G. Medeiros-Ribeiro, Y. A. Chang, and R. S. Williams, Self-assembled growth of epitaxial erbium disilicide nanowires on silicon (001), Appl. Phys. Lett. 76, 4004 (2000).
  25. Y. Chen, D. A. A. Ohlberg, and R. S. Williams, Nanowires of four epitaxial hexagonal silicides grown on Si(001), J. Appl. Phys. 91, 3213 (2002).
  26. Y. Cui, J. Chung, and J. Nogami, Controlling the width of self-assembled dysprosium silicide nanowires on the Si(001) surface, J. Phys. Condens. Matter 24, 045003 (2012).
  27. M. Dähne and M. Wanke, Metallic rare-earth silicide nanowires on silicon surfaces, J. Phys. Condens. Matter 25, 014012 (2013).
  28. D. E. Chang, A. S. Sørensen, P. R. Hemmer, and M. D. Lukin, Quantum optics with surface plasmons, Phys. Rev. Lett. 97, 053002 (2006).
  29. G. S. Snider and R. S. Williams, Nano/CMOS architectures using a field-programmable nanowire interconnect, Nanotechnology 18, 035204 (2007).
  30. I. Miccoli, F. Edler, H. Pfnür, S. Appelfeller, M. Dähne, K. Holtgrewe, S. Sanna, W. G. Schmidt, and C. Tegenkamp, Atomic size effects studied by transport in single silicide nanowires, Phys. Rev. B 93, 125412 (2016).
  31. H. Pfnür et al., Atomic wires on substrates: Physics between one and two dimensions, Surf. Sci. Rep. 79, 100629 (2024).
  32. H. W. Yeom, Y. K. Kim, E. Y. Lee, K.-D. Ryang, and P. G. Kang, Robust one-dimensional metallic band structure of silicide nanowires, Phys. Rev. Lett. 95, 205504 (2005).
  33. M. Wanke, K. Löser, G. Pruskil, D. V. Vyalikh, S. L. Molodtsov, S. Danzenbächer, C. Laubschat, and M. Dähne, Electronic properties of self-assembled rare-earth silicide nanowires on Si(001), Phys. Rev. B 83, 205417 (2011).
  34. S. Appelfeller, M. Franz, H.-F. Jirschik, J. Große, and M. Dähne, The electronics structure of Tb silicide nanowires on Si(001), New J. Phys. 18, 113005 (2016).
  35. K. Holtgrewe, S. Appelfeller, M. Franz, M. Dähne, and S. Sanna, Structure and one-dimensional metallicity of rare-earth silicide nanowires on Si(001), Phys. Rev. B 99, 214104 (2019).
  36. C. Zeng, P. R. C. Kent, T.-H. Kim, A.-P. Li, and H. H. Weitering, Charge-order fluctuations in one-dimensional silicides, Nat. Mater. 7, 539 (2008).
  37. S. Sanna, J. Plaickner, K. Holtgrewe, V. M. Wettig, E. Speiser, S. Chandola, and N. Esser, Spectroscopic analysis of rare-earth silicide structures on the Si(111) surface, Materials 14, 4104 (2021).
  38. C. Preinesberger, S. K. Becker, S. Vandré, T. Kalka, and M. Dähne, Structure of DySi2 nanowires on Si(001), J. Appl. Phys. 91, 1695 (2002).
  39. Z. He, M. Stevens, D. J. Smith, and P. A. Bennett, Dysprosium silicide nanowires on Si(110), Appl. Phys. Lett. 83, 5292 (2003).
  40. B. Z. Liu and J. Nogami, Growth of parallel rare-earth silicide nanowire arrays on vicinal Si(001), Nanotechnology 14, 873 (2003).
  41. C. Preinesberger, G. Pruskil, S. K. Becker, M. Dähne, D. V. Vyalikh, S. L. Molodtsov, C. Laubschat, and F. Schiller, Structure and electronic properties of dysprosium-silicide nanowires on vicinal Si(001), Appl. Phys. Lett. 87, 083107 (2005).
  42. M. Wanke, K. Löser, G. Pruskil, and M. Dähne, Structural and electronic properties of rare earth silicide nanowires on Si(557), Phys. Rev. B 79, 155428 (2009).
  43. M. Wanke, M. Franz, M. Vetterlein, G. Pruskil, C. Prohl, B. Höpfner, P. Stojanov, E. Huwald, J. D. Riley, and M. Dähne, Electronic properties of dysprosium silicide nanowires on Si(557), J. Appl. Phys. 108, 064304 (2010).
  44. A. Seiler, S. Ibrahimkutty, P. Wochner, R. Pradip, O. Waller, B. Krause, A. Plech, T. Baumbach, M. Fiederle, and S. Stankov, Thermal stability studies of DySi2 nanowires and nanoislands by in Situ GISAXS, J. Phys. Chem. C 120, 7365 (2016).
  45. J. Perri, E. Banks, and B. Post, Polymorphism of rare earth disilicides, J. Phys. Chem. 63, 2073 (1959).
  46. V. Eremenko, K. Meleshevich, Y. Buyanov, and P. Martsenyuk, Structure, composition and phase equilibria in dysprosium silicon alloys, Ukr. Khim. Zh. (Russ. Ed.) 60, 544 (1994).
  47. K. Xu, L. Chen, K. Chang, P. Wan, M. Li, Z. Deng, F. Huang, and Q. Huang, Thermodynamic description of the Dy–Si–C system in silicon carbide ceramics, CALPHAD: Comput. Coupling Phase Diagrams Thermochem. 68, 101738 (2020).
  48. V. Koleshko, V. Belitsky, and A. Khodin, Thin films of rare earth metal silicides, Thin Solid Films 141, 277 (1986).
  49. A. Travlos, N. Salamouras, and N. Boukos, Epitaxial dysprosium silicide films on silicon: Growth, structure and electrical properties, Thin Solid Films 397, 138 (2001).
  50. G. Ye, M. A. Crimp, and J. Nogami, Crystallographic study of self-assembled dysprosium silicide nanostructures on Si(001), Phys. Rev. B 74, 033104 (2006).
  51. G. Ye, J. Nogami, and M. A. Crimp, Dysprosium disilicide nanostructures on silicon(001) studied by scanning tunneling microscopy and transmission electron microscopy, Thin Solid Films 497, 48 (2006).
  52. B. Liu and J. Nogami, An STM study of the Si(001) (2×4)-Dy surface, Surf. Sci. 488, 399 (2001).
  53. B. Liu and J. Nogami, An STM study of the Si(001)(2×7)-Gd, Dy surface, Surf. Sci. 540, 136 (2003).
  54. B. Z. Liu and J. Nogami, A scanning tunneling microscopy study of dysprosium silicide nanowire growth on Si(001), J. Appl. Phys. 93, 593 (2003).
  55. J. Nogami, B. Z. Liu, M. V. Katkov, C. Ohbuchi, and N. O. Birge, Self-assembled rare-earth silicide nanowires on Si(001), Phys. Rev. B 63, 233305 (2001).
  56. S. Appelfeller, J. Heggemann, T. Niermann, M. Lehmann, and M. Dähne, Refined structure model of rare earth silicide nanowires on Si(001), Appl. Phys. Lett. 114, 093104 (2019).
  57. J. Heggemann, S. Appelfeller, T. Niermann, M. Lehmann, and M. Dähne, Internal atomic structure of terbium silicide nanowires on Si(001) capped by silicon, Surf. Sci. 696, 121563 (2020).
  58. See Supplemental Material at http://link.aps.org/supplemental/10.1103/4r3t-tr77, which includes Ref. [59], for further details about sample preparation and characterization, ab initio lattice dynamics calculations, and additional fit results of the PDOS of the NWs.
  59. I. Semitelou, A two-phase magnetic structure of DySi2, J. Magn. Magn. Mater. 267, 42 (2003).
  60. M. Seto, Y. Yoda, S. Kikuta, X. W. Zhang, and M. Ando, Observation of nuclear resonant scattering accompanied by phonon excitation using synchrotron radiation, Phys. Rev. Lett. 74, 3828 (1995).
  61. W. Sturhahn, T. S. Toellner, E. E. Alp, X. Zhang, M. Ando, Y. Yoda, S. Kikuta, M. Seto, C. W. Kimball, and B. Dabrowski, Phonon density of states measured by inelastic nuclear resonant scattering, Phys. Rev. Lett. 74, 3832 (1995).
  62. S. Stankov, R. Rüffer, M. Sladecek, M. Rennhofer, B. Sepiol, G. Vogl, N. Spiridis, T. Slezak, and J. Korecki, An ultrahigh vacuum system for in situ studies of thin films and nanostructures by nuclear resonance scattering of synchrotron radiation, Rev. Sci. Instrum. 79, 045108 (2008).
  63. R. Rüffer and A. I. Chumakov, Nuclear resonance beamline at ESRF, Hyperfine Interact. 97, 589 (1996).
  64. A. I. Chumakov, R. Rüffer, O. Leupold, A. Barla, H. Thiess, J. M. Gil, H. V. Alberto, R. C. Vilão, N. Ayres de Campos, V. G. Kohn, M. Gerken, and M. Lucht, Nuclear inelastic scattering with Dy161, Phys. Rev. B 63, 172301 (2001).
  65. A. I. Chumakov and W. Sturhahn, Experimental aspects of inelastic nuclear resonance scattering, Hyperfine Interact. 123, 781 (1999).
  66. A. I. Chumakov and V. G. Kohn, DOS: Evaluation of phonon density of states from nuclear resonant inelastic absorption, Hyperfine Interact. 125, 205 (2000).
  67. J. A. Perri, I. Binder, and B. Post, Rare earth “disilicides,” J. Phys. Chem. 63, 616 (1959).
  68. J.-C. G. Bunzli and V. K. Pecharsky, Handbook on the Physics and Chemistry of Rare Earths: Including Actinides (Elsevier, New York, 2016).
  69. G. Kresse and J. Furthmüller, Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set, Comput. Mater. Sci. 6, 15 (1996).
  70. J. P. Perdew, K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple, Phys. Rev. Lett. 77, 3865 (1996).
  71. P. E. Blöchl, Projector augmented-wave method, Phys. Rev. B 50, 17953 (1994).
  72. M. Kuzmin, M. P. J. Punkkinen, P. Laukkanen, R. E. Perälä, M. Ahola-Tuomi, T. Balasubramanian, and I. J. Väyrynen, Yb-induced (2×3) and (2×4) reconstructions on Si(100) studied by first-principles calculations and high-resolution core-level photoelectron spectroscopy, Phys. Rev. B 78, 045318 (2008).
  73. K. Parlinski, Z. Q. Li, and Y. Kawazoe, First-principles determination of the soft mode in cubic ZrO2, Phys. Rev. Lett. 78, 4063 (1997).
  74. K. Parlinski, Software phonon, Cracow, 2021.
  75. B. Fåk and B. Dorner, Institute Laue Langevin Technical, Report No. 92FA008S, 1992 (unpublished).
  76. J. Kalt, M. Sternik, B. Krause, I. Sergueev, M. Mikolasek, D. Merkel, D. Bessas, O. Sikora, T. Vitova, J. Göttlicher, R. Steininger, P. T. Jochym, A. Ptok, O. Leupold, H.-C. Wille, A. I. Chumakov, P. Piekarz, K. Parlinski, T. Baumbach, and S. Stankov, Lattice dynamics of endotaxial silicide nanowires, Phys. Rev. B 102, 195414 (2020).
  77. J. Kalt, M. Sternik, B. Krause, I. Sergueev, M. Mikolasek, D. Bessas, O. Sikora, T. Vitova, J. Göttlicher, R. Steininger, P. T. Jochym, A. Ptok, O. Leupold, H.-C. Wille, A. I. Chumakov, P. Piekarz, K. Parlinski, T. Baumbach, and S. Stankov, Lattice dynamics and polarization-dependent phonon damping in α-phase FeSi2 nanostructures, Phys. Rev. B 101, 165406 (2020).
  78. J. Kalt, M. Sternik, I. Sergeev, M. Mikolasek, D. Bessas, J. Göttlicher, B. Krause, T. Vitova, R. Steininger, O. Sikora, P. T. Jochym, O. Leupold, H.-C. Wille, A. I. Chumakov, P. Piekarz, K. Parlinski, T. Baumbach, and S. Stankov, Lattice dynamics of β−FeSi2 nanorods, Phys. Rev. B 106, 205411 (2022).
  79. L. Magaud, A. Pasturel, G. Kresse, and J. Hafner, Role of silicon vacancies in yttrium-disilicide compounds from ab initio calculations, Phys. Rev. B 55, 13479 (1997).
  80. Z. He, D. J. Smith, and P. A. Bennett, Endotaxial silicide nanowires, Phys. Rev. Lett. 93, 256102 (2004).

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Phys. Rev. Lett. 135, 256202– Published 17 December, 2025
  • Received 7 September 2024
  • Revised 31 October 2025
  • Accepted 20 November 2025
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