Electron–phonon interaction and thermal boundary resistance at the interfaces of Ge2Sb2Te5with metals and dielectrics

Campi, Davide; Baldi, Edoardo; Graceffa, G; Sosso, Gabriele C.; Bernasconi, Marco

doi:10.1088/0953-8984/27/17/175009

Cited by 8 publications

(5 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figures 3c, d show the TBC between GST and two different thicknesses of W. The TBC in h-GST is significantly suppressed compared to c-GST. A similar reduction in TBC has been experimentally and theoretically observed at GST/ metal interfaces, which were attributed to the formation of a 2-nm interfacial layer 49 and increased electron-phonon contribution to the interfacial resistance 50 . According to our TEM images, we do not observe an additional interfacial layer after cubic to hexagonal phase transition.…”

Section: Resultssupporting

confidence: 78%

Interface controlled thermal resistances of ultra-thin chalcogenide-based phase change memory devices

et al. 2021

View full text Add to dashboard Cite

Phase change memory (PCM) is a rapidly growing technology that not only offers advancements in storage-class memories but also enables in-memory data processing to overcome the von Neumann bottleneck. In PCMs, data storage is driven by thermal excitation. However, there is limited research regarding PCM thermal properties at length scales close to the memory cell dimensions. Our work presents a new paradigm to manage thermal transport in memory cells by manipulating the interfacial thermal resistance between the phase change unit and the electrodes without incorporating additional insulating layers. Experimental measurements show a substantial change in interfacial thermal resistance as GST transitions from cubic to hexagonal crystal structure, resulting in a factor of 4 reduction in the effective thermal conductivity. Simulations reveal that interfacial resistance between PCM and its adjacent layer can reduce the reset current for 20 and 120 nm diameter devices by up to ~ 40% and ~ 50%, respectively. These thermal insights present a new opportunity to reduce power and operating currents in PCMs.

show abstract

Section: Resultssupporting

confidence: 78%

Interface controlled thermal resistances of ultra-thin chalcogenide-based phase change memory devices

et al. 2021

View full text Add to dashboard Cite

show abstract

“…[50]. Phonon band structure has been reported for some of these structures in the works of Campi et al [31,51].…”

Section: (Gete) 2 (Sb 2 Te 3 ) (Gst225)mentioning

confidence: 95%

Ab initio density functional theory study of the electronic, dynamic, and thermoelectric properties of the crystalline pseudobinary chalcogenide (GeTe)x/(Sb2Te3)
Ibarra-Hernández
¹
,
Raty
²

2018
Phys. Rev. B

View full text Add to dashboard Cite

We use ab initio density functional theory calculations to understand the electronic, dynamical, and thermoelectric behavior of layered crystalline phase-change materials. We perform calculations on the pseudobinary compounds (GeTe) x /(Sb 2 Te 3 ) (GST) with x = 1, 2, and 3. Since the stable configuration of these compounds remains somehow unsettled, we study one stacking configuration for GST124 (x = 1), three for GST225 (x = 2), and two for GST326 (x = 3). A supercell approach is used to check the dynamical stability of the systems while thermoelectric properties are obtained by solving the Boltzmann transport equation. We report that the most accepted stacking configuration of GST124, GST225, and GST326 have metallic character and for the case of x = 2 and 3, those are the ones with the lowest energy. However, we find the metallic of GST326 configuration to be dynamically unstable. In general, our values of the Seebeck coefficient and thermal conductivity for compounds with x = 1 and 2 agree very well with the available experimental data. The small differences that we observe with respect to experimental data are attributed to the disorder that is present experimentally and that we have not taken into account. We do not find a Dirac cone in the electronic band structure of GST225, contrarily to previous reports. We attribute this due to the theoretical strain induced by the choice of the pseudopotential.

show abstract

“…This instability is actually removed by adding a vdW interaction according to Grimme [26] as discussed in Ref. [50]. Therefore, the thermal conductivity has been computed here using the PBE functional supplemented by the vdW interaction of Ref.…”

Section: Ge 2 Sb 2 Tementioning

confidence: 99%

First-principles calculation of lattice thermal conductivity in crystalline phase change materials: GeTe, Sb2Te3 , and Ge2
Campi
¹
,
Paulatto
²
,
Fugallo
³

et al. 2017
Phys. Rev. B
109
17
85
0
View full text Add to dashboard Cite

Thermal transport is a key feature for the operation of phase change memory devices which rest on a fast and reversible transformation between the crystalline and amorphous phases of chalcogenide alloys upon Joule heating. In this paper we report on the ab initio calculations of bulk thermal conductivity of the prototypical phase change compounds Ge 2 Sb 2 Te 5 and GeTe in their crystalline form. The related Sb 2 Te 3 compound is also investigated for the sake of comparison. Thermal conductivity is obtained from the solution of the Boltzmann transport equation with phonon scattering rates computed within density functional perturbation theory. The calculations show that the large spread in the experimental data on the lattice thermal conductivity of GeTe is due to a variable content of Ge vacancies which at concentrations realized experimentally can halve the bulk thermal conductivity with respect to the ideal crystal. We show that the very low thermal conductivity of hexagonal Ge 2 Sb 2 Te 5 of about 0.45 W m −1 K −1 measured experimentally is also resulting from disorder in the form of a random distribution of Ge/Sb atoms in one sublattice.

show abstract

Electron–phonon interaction and thermal boundary resistance at the interfaces of Ge₂Sb₂Te₅with metals and dielectrics

Cited by 8 publications

References 31 publications

Interface controlled thermal resistances of ultra-thin chalcogenide-based phase change memory devices

Interface controlled thermal resistances of ultra-thin chalcogenide-based phase change memory devices

Ab initio density functional theory study of the electronic, dynamic, and thermoelectric properties of the crystalline pseudobinary chalcogenide (GeTe)x/(Sb2Te3)
Ibarra-Hernández
¹
,
Raty
²

2018
Phys. Rev. B

First-principles calculation of lattice thermal conductivity in crystalline phase change materials: GeTe, Sb2Te3 , and Ge2
Campi
¹
,
Paulatto
²
,
Fugallo
³

et al. 2017
Phys. Rev. B
109
17
85
0
View full text Add to dashboard Cite

Contact Info

Product

Resources

About

Electron–phonon interaction and thermal boundary resistance at the interfaces of Ge2Sb2Te5with metals and dielectrics

Cited by 8 publications

References 31 publications

Interface controlled thermal resistances of ultra-thin chalcogenide-based phase change memory devices

Interface controlled thermal resistances of ultra-thin chalcogenide-based phase change memory devices

Ab initio density functional theory study of the electronic, dynamic, and thermoelectric properties of the crystalline pseudobinary chalcogenide (GeTe)x/(Sb2Te3)Ibarra-Hernández1, Raty2 2018Phys. Rev. B

First-principles calculation of lattice thermal conductivity in crystalline phase change materials: GeTe, Sb2Te3 , and Ge2Campi1, Paulatto2, Fugallo3 et al. 2017Phys. Rev. B10917850View full textAdd to dashboardCite

Contact Info

Product

Resources

About

Electron–phonon interaction and thermal boundary resistance at the interfaces of Ge₂Sb₂Te₅with metals and dielectrics

Ab initio density functional theory study of the electronic, dynamic, and thermoelectric properties of the crystalline pseudobinary chalcogenide (GeTe)x/(Sb2Te3)
Ibarra-Hernández
¹
,
Raty
²

2018
Phys. Rev. B

First-principles calculation of lattice thermal conductivity in crystalline phase change materials: GeTe, Sb2Te3 , and Ge2
Campi
¹
,
Paulatto
²
,
Fugallo
³

et al. 2017
Phys. Rev. B
109
17
85
0
View full text Add to dashboard Cite