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Electronic Band Structure Engineering and Enhanced Thermoelectric Transport Properties in Pb-Doped BiCuOS Oxysulfide
Chemistry of Materials ( IF 7.2 ) Pub Date : 2018-01-19 00:00:00 , DOI: 10.1021/acs.chemmater.7b04989 Jean-Baptiste Labégorre 1 , Rabih Al Rahal Al Orabi 2, 3 , Agathe Virfeu 2 , Jacinthe Gamon 4, 5 , Philippe Barboux 5 , Lauriane Pautrot-d’Alençon 4 , Thierry Le Mercier 4 , David Berthebaud 1 , Antoine Maignan 1 , Emmanuel Guilmeau 1
Chemistry of Materials ( IF 7.2 ) Pub Date : 2018-01-19 00:00:00 , DOI: 10.1021/acs.chemmater.7b04989 Jean-Baptiste Labégorre 1 , Rabih Al Rahal Al Orabi 2, 3 , Agathe Virfeu 2 , Jacinthe Gamon 4, 5 , Philippe Barboux 5 , Lauriane Pautrot-d’Alençon 4 , Thierry Le Mercier 4 , David Berthebaud 1 , Antoine Maignan 1 , Emmanuel Guilmeau 1
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In this paper, Bi1–xPbxCuOS samples (0 ≤ x ≤ 0.05) have been synthesized with a simple and scalable ball-milling process, followed by a reactive Spark Plasma Sintering. Our results highlight that, Pb for Bi substitution increases the charge carriers concentration by more than 2 orders of magnitude from 1.4 × 1017 cm–3 to 2.6 × 1019 cm–3 for x = 0 and x = 0.05, respectively. As a result, the electrical resistivity is divided by more than 50 at room temperature and the Seebeck coefficient drops from 707 μV K–1 to 265 μV K–1 where our experimental results are supported with density functional theory (DFT) calculations. Electronic structure calculations show that, just below the top of the valence band, several other bands are present and may contribute to the transport properties with appropriate tuning of the heavy-light valence band and the position of the Fermi level. Pb doping increases the number of holes pockets and several band degeneracies appear around the Fermi level, leading to a drastic enhancement of the power factor up to 0.2 mW m–1 K–2 at 700 K. This is 5 times higher than the value of the pristine compound. The intrinsically low thermal conductivity of 0.7 W m–1 K–1 at 700 K is interpreted on the basis of vibrational properties calculations within the Density Functional Perturbation Theory (DFPT) approach. It indicates that soft acoustic modes along the Γ–Z direction suggest weak interatomic bonding between the layers and possible strong anharmonicity. The power factor being enhanced with a minimal impact on the thermal conductivity, the figure of merit ZT reaches 0.2 at 700 K for x = 0.05. To the best of our knowledge, it is considered the best reported value among the family of oxysulfides
中文翻译：
Pb掺杂BiCuOS氧硫化物的电子能带结构工程和增强的热电输运性质
在本文中，铋1- X铅X CuOS样品（0≤ X ≤0.05）已被合成以简单，可扩展的球磨处理，接着通过反应性放电等离子烧结。我们的结果表明，对于x = 0和x = 0.05，用于Bi取代的Pb将电荷载流子浓度从1.4×10 17 cm –3增大到2.6×10 19 cm –3超过2个数量级。结果，室温下电阻率除以50以上，塞贝克系数从707μVK –1降至265μVK –1我们的实验结果得到密度泛函理论（DFT）计算的支持。电子结构计算表明，在价带顶部的正下方，还存在其他几个带，它们可能通过适当调整重轻价带和费米能级的位置而有助于传输性质。铅掺杂增加了空穴穴的数量，费米能级附近出现了几个能带简并性，从而导致功率因数在700 K时急剧提高到0.2 mW m –1 K –2。这是Pb值的5倍。原始化合物。0.7 W m –1 K –1的固有低热导率密度泛函扰动理论（DFPT）方法中基于振动特性的计算来解释700 K时的温度。这表明沿Γ - Z方向的软声模表明层之间的原子间键合较弱，并可能存在强非谐性。功率因数在对导热系数的影响最小的情况下得以提高，当x = 0.05时，品质因数ZT在700 K下达到0.2 。据我们所知，它被认为是氧硫化物家族中报告值最高的一种
更新日期：2018-01-19
中文翻译：
Pb掺杂BiCuOS氧硫化物的电子能带结构工程和增强的热电输运性质
在本文中，铋1- X铅X CuOS样品（0≤ X ≤0.05）已被合成以简单，可扩展的球磨处理，接着通过反应性放电等离子烧结。我们的结果表明，对于x = 0和x = 0.05，用于Bi取代的Pb将电荷载流子浓度从1.4×10 17 cm –3增大到2.6×10 19 cm –3超过2个数量级。结果，室温下电阻率除以50以上，塞贝克系数从707μVK –1降至265μVK –1我们的实验结果得到密度泛函理论（DFT）计算的支持。电子结构计算表明，在价带顶部的正下方，还存在其他几个带，它们可能通过适当调整重轻价带和费米能级的位置而有助于传输性质。铅掺杂增加了空穴穴的数量，费米能级附近出现了几个能带简并性，从而导致功率因数在700 K时急剧提高到0.2 mW m –1 K –2。这是Pb值的5倍。原始化合物。0.7 W m –1 K –1的固有低热导率密度泛函扰动理论（DFPT）方法中基于振动特性的计算来解释700 K时的温度。这表明沿Γ - Z方向的软声模表明层之间的原子间键合较弱，并可能存在强非谐性。功率因数在对导热系数的影响最小的情况下得以提高，当x = 0.05时，品质因数ZT在700 K下达到0.2 。据我们所知，它被认为是氧硫化物家族中报告值最高的一种
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