Data for the publication "Size Effect on the Thermal Conductivity of a Type-I Clathrate"

Context and methodology 

This repository contains the data behind the publication "Size Effect on the Thermal Conductivity of a Type-I Clathrate" (10.3390/cryst13030453).

The dataset was created manually by collecting and ordering the relevant data.

The publication presents and discusses the thermal conductivity of type-I clathrate mesowires with different diameters, measured with a 3-omega technique. The fitting operations and simulations were conducted using data analysis software from OriginLab. 

Description of the data 

Fig5 illustrates the data analysis behind a 3-omega thermal conductivity measurement: Fig5a.dat contains the measured frequency dependence of a 3rd harmonic voltage signal "V_3omega(f)" of a 25um Pt wire, as well as a fit to the data. Fig5b.dat is a representative dataset of a 3-omega measurement done on one 920nm mesowire.  It contains measurements of the 3rd harmonic voltage "V_3omega" as a function of excitation current "I^3" for temperatures ranging from 300K to 80K, in 20K steps and linear fits to the data, demonstrating the "V_3omega" ~ "I^3" dependence. 

Fig6 presents the thermal conductivity and electrical resistivity of the mesowires. The results are the average of measurements of two different mesowires, the dispersion being represented by an error bar: Fig6a.dat contains the lattice contribution to the thermal conductivity "kappa_ph" with an error bar "kappa_ph (Er+-)" and the electronic contribution "kappa_el" with an error bar "kappa_el (Er+-)" as a function of temperature "T" for mesowires of three different diameters 630nm, 920nm, and 1260nm.Fig6b.dat contains the electrical resistivity "rho" with an error bar "rho (Er+-)" as a function of temperature "T" for mesowires of three different diameters 630nm, 920nm, and 1260nm.  

Fig7 compares the accuracy of a modified Callaway model and the original Callaway model in describing our data: Fig7a.dat contains the lattice contribution data "kappa_ph" for the mesowires from Fig6a, as well as a fit to bulk data (obtained from M. S. Ikeda for a different publication and therefore not inlcuded here) using a modified Callaway model. Simulations of the lattice thermal conductivity based on the model with the obtained fitting parameters are included for each mesowire diameter.Fig7b.dat contains "kappa_ph" for the mesowires from Fig6a, as well as a fit to bulk data using the original Callaway and subsequent simulations for the mesowires. 

Fig8 contains "kappa_ph" with an error bar "kappa_ph (Er+-)" as a function of boundary scattering length "lambda", as well as simulations using both the modified and the original Callaway model.

Fig9 contains the calculated figure of merit "ZT" with an error bar "ZT (Er+-)" as a function of temperature "T" for mesowires of three different diameters 630nm, 920nm, and 1260nm.  

Technical details

For each figure there is a corresponding file containing the data shown in the figure. Data files, with the extension .dat, are text files, and named logically after data they contain. 

The dataset does not require any specific software for reading.

背景与研究方法
本仓库包含发表于《Ⅰ型笼型化合物热导率的尺寸效应》（DOI: 10.3390/cryst13030453）的配套数据集。
本数据集通过手动收集并整理相关数据构建而成。
该论文分析并讨论了采用3ω法（3-omega technique）测量的不同直径Ⅰ型笼型化合物（type-I clathrate）微线的热导率。数据拟合与模拟操作均采用OriginLab公司的数据分析软件完成。

数据集说明
图5展示了3ω法热导率测量的数据分析流程：Fig5a.dat包含了25μm铂丝的三次谐波电压信号V_3ω(f)随频率的变化实测数据，以及对应的数据拟合结果。Fig5b.dat为单根920nm微线的3ω法测量代表性数据集，其包含了在300K至80K区间（步长20K）内，三次谐波电压V_3ω随激发电流三次方I^3的变化实测数据，以及对该数据的线性拟合结果，验证了V_3ω与I^3的正比关系。
图6展示了微线的热导率与电阻率数据。所有结果均为两根独立微线测量结果的平均值，数据离散程度以误差棒表示：Fig6a.dat包含了三种不同直径（630nm、920nm、1260nm）的微线的声子热导率贡献项κ_ph（带误差棒κ_ph(Er±)）与电子热导率贡献项κ_el（带误差棒κ_el(Er±)）随温度T的变化关系。Fig6b.dat包含了三种直径微线的电阻率ρ（带误差棒ρ(Er±)）随温度T的变化关系。
图7对比了修正版卡洛威模型（Callaway model）与原始卡洛威模型对本数据集的拟合精度：Fig7a.dat包含了Fig6a中微线的声子热导率贡献项κ_ph数据，以及采用修正版卡洛威模型对块体数据（该数据由M. S. Ikeda为另一项研究获取，未包含在本数据集中）的拟合结果。同时包含了基于该模型与拟合参数，针对不同直径微线的晶格热导率模拟结果。Fig7b.dat包含了Fig6a中微线的声子热导率贡献项κ_ph数据，以及采用原始卡洛威模型对块体数据的拟合结果，与后续针对各微线的模拟结果。
图8展示了声子热导率贡献项κ_ph（带误差棒κ_ph(Er±)）随边界散射长度λ的变化关系，同时包含了采用修正版与原始卡洛威模型得到的模拟结果。
图9展示了三种直径（630nm、920nm、1260nm）的微线的计算品质因数ZT（带误差棒ZT(Er±)）随温度T的变化关系。

技术细节
每个图表均对应一个包含该图表数据的数据文件。扩展名为.dat的数据文件均为文本文件，其命名逻辑与其包含的数据内容相匹配。
本数据集无需专用软件即可读取。