Über Zweistoffsysteme mit Germanium. I. Germanium/Aluminium, Germanium/Zinn und Germanium/Silicium

Stöhr, Herbert; Klemm, Wilhelm

doi:10.1002/zaac.19392410401

Cited by 235 publications

(66 citation statements)

References 3 publications

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“…As the layer thickness increase, the peaks in the phonon transmission disappear, due to the loss of the original momentum and random traveling directions of the phonons after scattering within a thick alloyed layer, i.e., strong mode conversion of the phonons across the alloyed layer. 47 The thermal conductance of the 2.27 nm alloy layer itself is estimated to be ~4.4 GW/m 2 K, which is significantly larger than the overall thermal conductance from our calculation. This indicates that the interface thermal resistance across the alloyed interface is mainly governed by the adjacent regions between the bulk materials and the alloyed layer, where atoms slightly deviate from their original position in a bulk crystal.…”

Section: Alloyed Interfacecontrasting

confidence: 52%

Effect of lattice mismatch on phonon transmission and interface thermal conductance across dissimilar material interfaces

Yang

2012

Phys. Rev. B

139

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When phonons transport across a material interface, they experience reflection, transmission and mode conversion, which results in a local temperature jump at interface and thus dramatically changes the thermal conductivity of nanostructured materials. Phonon transmission across lattice-matched interfaces has been studied extensively in recent years with the atomistic Green's function (AGF) approach, which usually uses one unit cell to represent the cross-section along the interface. However, modeling phonon transmission across realistic material interfaces is much more challenging because realistic interfaces are usually latticemismatched ones with atomic reconstruction, defects, and species mixing, which demands a larger cross-sectional area for the AGF simulation. In this paper, an integrated molecular dynamics (MD) and AGF approach is developed to study the phonon transmission across latticemismatched interfaces. MD simulation is used to simulate atomic reconstruction close to the 1 Email: Ronggui.Yang@Colorado.Edu interface. The recursive AGF approach is then employed for the first time to calculate frequencydependent phonon transmission across lattice-mismatched interfaces with defects and species mixing, which addresses the numerical challenge in calculating phonon transmission for a relatively large cross-sectional area with reduced computational cost. The study of the relaxed interface formed from two semi-infinite bulk materials shows that lattice mismatch increases the lattice disorder and decreases the adhesion energy, which in turn lowers phonon transmission and reduces the interface thermal conductance across lattice-mismatched interfaces. Low-frequency phonons can be significantly scattered by increasing the defect size across the interface while high frequency phonons can be scattered almost completely (phonon transmission <0.1) across an alloyed layer as thin as 2.27 nm. The effect of lattice-mismatch on phonon transmission becomes smaller for interfaces with defects and species mixing. The effect of annealing temperature on the Si/Ge interface thermal conductance was studied. A significant reduction of the Si/Ge interface thermal conductance was observed for a lattice-mismatched interface when annealed at high temperature, which agrees well with the available experimental data in literature.

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Section: Alloyed Interfacecontrasting

confidence: 52%

Effect of lattice mismatch on phonon transmission and interface thermal conductance across dissimilar material interfaces

Yang

2012

Phys. Rev. B

139

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“…Garg et al [22] has applied this approach to Si-Ge alloys using the force constants from DFPT and reached excellent with the experimental data [23,24].…”

Section: Alloy Modelingmentioning

confidence: 84%

“…Previous experimental and theoretical studies on Si-Ge alloys [22][23][24] have found dramatic decrease in the lattice thermal conductivity from pure Si and Ge.…”

Section: Introductionmentioning

confidence: 88%

Phonon conduction in PbSe, PbTe, and PbTe1−xSexfrom first-principles calculations

et al. 2012

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We apply first-principles calculations to lead selenide (PbSe) and lead telluride (PbTe) and their alloys (PbTe 1-x Se x ) which are potentially good thermoelectric materials, to investigate their phonon transport properties. By accurately reproducing the lattice thermal conductivity, we validate the approaches adopted in this work. We then compare and contrast PbSe and PbTe, evaluate the importance of the optical phonons to lattice thermal conductivity, and estimate the impacts of nanostructuring and alloying on further reducing the lattice thermal conductivity. The results indicate that: 1) the optical phonons are important not only because they directly comprise over 20% of the lattice thermal conductivity, but also because they provide strong scattering channels for acoustic phonons, which is crucial for the low thermal conductivity; 2) nanostructures of less than ~10 nm are needed to reduce the lattice thermal conductivity for pure PbSe and PbTe; 3) alloying should be a relatively effective way to reduce the lattice thermal conductivity.

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“…One may note that the thermal conductivity of ≃1.3 Wcm −1 K −1 in Si at room temperature is almost reduced by an order of magnitude (≃0.1 Wcm −1 K −1 ) with alloying with Ge in Si-Ge alloys. 37,44 Thus with Sn being more massive, one may expect further reduction in the thermal conductivity in Si-Ge-Sn ternary alloys.…”

mentioning

confidence: 99%

Band gap engineering of Si-Ge alloys for mid-temperature thermoelectric applications

Pulikkotil

Auluck

2015

AIP Advances

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The viability of Si-Ge alloys in thermoelectric applications lies in its high figure-of-merit, non-toxicity and earth-abundance. However, what restricts its wider acceptance is its operation temperature (above 1000 K) which is primarily due to its electronic band gap. By means of density functional theory calculations, we propose that iso-electronic Sn substitutions in Si-Ge can not only lower its operation to mid-temperature range but also deliver a high thermoelectric performance. While calculations find a near invariance in the magnitude of thermopower, empirical models indicate that the materials thermal conductivity would also reduce, thereby substantiating that Si-Ge-Sn alloys are promising mid-temperature thermoelectrics.

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Über Zweistoffsysteme mit Germanium. I. Germanium/Aluminium, Germanium/Zinn und Germanium/Silicium

Cited by 235 publications

References 3 publications

Effect of lattice mismatch on phonon transmission and interface thermal conductance across dissimilar material interfaces

Effect of lattice mismatch on phonon transmission and interface thermal conductance across dissimilar material interfaces

Phonon conduction in PbSe, PbTe, and PbTe1−xSexfrom first-principles calculations

Band gap engineering of Si-Ge alloys for mid-temperature thermoelectric applications

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