Thermal conductivity of biaxial-strained MoS<sub>2</sub>: sensitive strain dependence and size-dependent reduction rate

Zhu, Liyan; Zhang, Tingting; Sun, Ziming; Li, Jianhua; Chen, Guibin; Yang, Shengyuan A.

doi:10.1088/0957-4484/26/46/465707

Cited by 69 publications

(32 citation statements)

References 45 publications

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“…Additionally, our first principles calculations demonstrate that the lattice thermal conductivity decreases with increasing biaxial tensile strain, as shown in Figure S7, in agreement with previous theoretical studies of 2D materials. 12,14,15,17,18 Under biaxial compressive strain, first principles calculations give imaginary phonon modes for bulk In conclusion, the ripple geometry observed here has negligible effect on phonon scattering because the radius of curvatures of the compression-induced ripples in the 2D layers are on the micrometer scale and much larger than both the mean free paths and wavelengths of heat-carrying phonons. In addition, the ripples relax the compressive strain in the top layers, while the tensile strains in the bottom layers are calculated to be insufficient to cause apparent suppression of the thermal conductivity.…”

Section: Main Textmentioning

confidence: 63%

“…For example, severe rippling in graphene was shown to generate a long-range scattering potential for electrons and strongly suppress their weak localization. [9][10][11] In addition, the effects of ripples and kinks on thermal conductivity () in 2D materials has been considered in several theoretical studies, including unique strain effects, [12][13][14][15][16][17][18] which can influence the performance and thermomechanical reliability of emerging 2D devices. [19][20][21] Contrary to bulk materials for which compressive and tensile strains generally increase and decrease the thermal conductivity, 14 respectively, molecular dynamics studies have suggested that both tensile and compressive strains reduce the thermal conductivities of graphene and MoS2.…”

Section: Main Textmentioning

confidence: 99%

“…MoS2 suggesting structural instability, likely due to the energetically favorable rippling geometry. While relaxation of the compressive strain in the top layer via the ripples of micrometer curvature results in negligible effect on the phonon dispersion and scattering, tensile strain at a level of ~0.14% in the bottom layers may reduce basal plane thermal conductivity by a few percent 18. …”

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confidence: 99%

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Phonon interaction with ripples and defects in thin layered molybdenum disulfide

Smith

Lindsay

Kim

et al. 2019

Applied Physics Letters

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Compared to other extrinsic phonon scattering mechanisms such as surface and interior defects, phonon scattering and lattice thermal resistance due to structural rippling in few-layer two-dimensional (2D) materials is under-examined. Here the temperature-dependent basalplane thermal conductivities () of one rippled and four flat molybdenum disulfide (MoS2) samples are measured with a four-probe thermal transport measurement method. A flat 18 nm thick sample and a rippled 20 nm thick sample show similar peak  values of 122±17 and 129±19 W m-1 K-1 , respectively. In comparison, a 32 nm thick flat sample has a peak  of only 58±11 W m-1 K-1 despite having increased thickness. The peak thermal conductivities of the five samples decrease with increasing integrated Raman intensity caused by defects in the frequency range of the phonon band gap in MoS2. In conjunction with the experimental findings, theoretical calculations of the temperature-, thickness-, strain-, and defect-dependent  of thin MoS2 layers reveal the importance of interior defect scattering over scattering from compression-induced ripples and surface defects in these samples. The results further clarify the conditions where ripples are important in determining the basal plane thermal resistance in layered systems.

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Section: Main Textmentioning

confidence: 63%

Section: Main Textmentioning

confidence: 99%

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confidence: 99%

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Phonon interaction with ripples and defects in thin layered molybdenum disulfide

Smith

Lindsay

Kim

et al. 2019

Applied Physics Letters

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“…We could not uncover any meaningful correlation between strain and the thermal diffusivity from the experimental data. The spread in the strain between the de-vices estimated from the resonance frequency is no more than 0.4%, which should result in a spread in the thermal conductivity of approximately 3% [36]. The measured device-to-device spread is significantly larger and straindependence is thus not the cause of the observed variations.…”

Section: B Relation Between Mechanical and Thermal Propertiesmentioning

confidence: 84%

Transient thermal characterization of suspended monolayer MoS2

Dolleman

Lloyd

Lee

et al. 2018

Phys. Rev. Materials

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We measure the thermal time constants of suspended single layer molybdenum disulfide drums by their thermomechanical response to a high-frequency modulated laser. From this measurement the thermal diffusivity of single layer MoS2 is found to be 1.14 × 10 −5 m 2 /s on average. Using a model for the thermal time constants and a model assuming continuum heat transport, we extract thermal conductivities at room temperature between 10 to 40 W/(m·K). Significant device-to-device variation in the thermal diffusivity is observed. Based on statistical analysis we conclude that these variations in thermal diffusivity are caused by microscopic defects that have a large impact on phonon scattering, but do not affect the resonance frequency and damping of the membrane's lowest eigenmode. By combining the experimental thermal diffusivity with literature values of the thermal conductivity, a method is presented to determine the specific heat of suspended 2D materials, which is estimated to be 255 ± 104 J/(kg·K) for single layer MoS2.

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“…Small κ could jeopardize heat dissipation of TMD-based electronics, and techniques to enhance the cross-plane thermal conductivity are required. Previous theoretical studies of strain's effect on thermal conductivity in TMDs have reached inconsistent conclusions [38][39][40][41][42], and experimental studies have not yet been reported. Thus, exploring the tunability of thermal conductivity in TMDs with strain will not only have scientific significance, but also inform thermal management techniques in all TMD-based electronic devices.…”

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confidence: 96%

Thermal Conductivity Enhancement in MoS2 under Extreme Strain

et al. 2019

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Due to their weak interlayer bonding, van der Waals (vdW) solids are very sensitive to external stimuli such as strain. Experimental studies of strain tuning of thermal properties in vdW solids have not yet been reported. Under ~9% cross-plane compressive strain created by hydrostatic pressure in a diamond anvil cell, we observed an increase of cross-plane thermal conductivity in bulk MoS 2 from 3.5 Wm-1 K-1 to about 25 Wm-1 K-1 , measured with a picosecond transient thermoreflectance technique. First-principles calculations and coherent phonon spectroscopy experiments reveal that this drastic change arises from the strain-enhanced interlayer interaction, heavily modified phonon dispersions, and decrease in phonon lifetimes due to unbundling effect along cross-plane direction. The contribution from the change of electronic thermal conductivity is negligible. Our results suggest possible parallel tuning of structural, thermal and electrical properties of vdW solids with strain in multi-physics devices. Main Text Strain is an effective tool to tune physical properties in a wide range of materials [1-4]. In transition metal dichalcogenides (TMDs), a family of two-dimensional (2D) van der Waals (vdW) solids, strain can alter the interlayer distance, as well as bond strength, length and angle between the transition metal and chalcogen atoms, modifying the interatomic orbital coupling, interlayer wavefunction overlap and valence band splitting [5-7]. Changes in these physical parameters can modulate electronic and phononic properties to a great extent. For example, the electronic band gap and phonon Raman peaks in TMDs have been shown experimentally very sensitive to strain, with an A 1g phonon Raman shift as large as ~5-6 cm-1 /% [8-13]. In traditional mechanical bending/stretching experiments, the 2D materials sit on a flexible substrate and strain is determined

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Thermal conductivity of biaxial-strained MoS₂: sensitive strain dependence and size-dependent reduction rate

Cited by 69 publications

References 45 publications

Phonon interaction with ripples and defects in thin layered molybdenum disulfide

Phonon interaction with ripples and defects in thin layered molybdenum disulfide

Transient thermal characterization of suspended monolayer MoS2

Thermal Conductivity Enhancement in MoS2 under Extreme Strain

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Thermal conductivity of biaxial-strained MoS2: sensitive strain dependence and size-dependent reduction rate

Cited by 69 publications

References 45 publications

Phonon interaction with ripples and defects in thin layered molybdenum disulfide

Phonon interaction with ripples and defects in thin layered molybdenum disulfide

Transient thermal characterization of suspended monolayer MoS2

Thermal Conductivity Enhancement in MoS2 under Extreme Strain

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Product

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Thermal conductivity of biaxial-strained MoS₂: sensitive strain dependence and size-dependent reduction rate