采用密度泛函理论研究了电子和空穴掺杂PtSb $_2$的热电性质。我们的研究结果表明，对于掺杂的0.04孔每单元电池（1.5 $\times10^{20}$ cm $^{-3}$）的PtSb $_2$显示出高的塞贝克系数在室温下，这也可以实现在其他温度下通过控制载流子浓度（电子和空穴）。当掺杂超过约0.20个电子/空穴/晶胞时，电导率变得与温度无关。在800 K时，电子和空穴掺杂的PtSb $_2$的优值分别为0.13和0.21。在一定的掺杂水平下，预测了具有相同基质材料的热电效率。
英文摘要：
We employ density functional theory to investigate the thermoelectric properties of electron and hole doped PtSb$_2$. Our results show that for doping of 0.04 holes per unit cell (1.5$\times10^{20}$ cm$^{-3}$) PtSb$_2$ shows a high Seebeck coefficient at room temperature, which can also be achieved at other temperatures by controlling the carrier concentration (both electron and hole). The electrical conductivity becomes temperature independent when the doping exceeds about 0.20 electrons/holes per unit cell. The figure of merit at 800 K in electron and hole doped PtSb$_2$ is 0.13 and 0.21, respectively. The thermoelectric efficiency with same host material are predicted for certain doping levels.
We report giant anisotropy in thermoelectric power factor ($S^2σ$) of marcasite structure-type PtSb$_{1.4}$Sn$_{0.6}$. PtSb$_{1.4}$Sn$_{0.6}$, synthesized using ambient pressure flux growth method upon mixing Sb and Sn on the same atomic site, is a new phase different from both PtSb$_2$ and PtSn$_2$ that crystallize in the cubic $Pa\bar{3}$ pyrite and $Fm\bar{3}m$ fluorite unit cell symmetry, respectively. Giant difference in $S^2σ$ for heat flow applied along different principal directions of the orthorhombic unit cell mostly stems from anisotropic Seebeck coefficients.
Thermoelectricity is a promising avenue for harvesting energy but large-scale applications are still hampered by the lack of highly-efficient low-cost materials. Recently, Fe$_2YZ$ Heusler compounds were predicted theoretically to be interesting candidates with large thermoelectric power factor. Here, we show that under doping conditions compatible with thermoelectric applications, these materials are prone to an unexpected magnetic instability detrimental to their thermoelectric performance. We rationalize the physics at the origin of this instability, provide guidelines for avoiding it and d…
Using the density functional theory (DFT) in combination with Boltzmann transport theory, the influence of Mg concentrations (x) doping on the thermoelectric properties of Hg1-xMgxSe ternary alloys was systematically investigated. The generalized gradient approximations of Perdew-Burke-Ernzerhof (GGA-PBE) have been used to illustrate the exchange correlation potential. Various thermoelectric transport parameters, such as the Seebeck coefficient (S), the thermal conductivity over relaxation time, the electrical conductivity over relaxation time, the power factor (PF) and the figure of merit (ZT…
The record-breaking thermoelectric performance of tin selenide (SnSe) has motivated the investigation of analogue compounds with the same structure. A promising candidate that emerged recently is germanium selenide (GeSe). Here, using extensive first-principles calculations of the hole-phonon and hole-impurity scattering, we investigate the thermoelectric transport properties of the orthorhombic phase of p-doped GeSe. We predict outstanding thermoelectric performance for GeSe over a broad range of temperatures due to its high Seebeck coefficients, extremely low Lorenz numbers, ultralow total t…
We report the synthesis and thermoelectric transport properties of As-doped layered pnictogen oxyselenides NdO0.8F0.2Sb1-xAsxSe2 (x < 0.7), which are predicted to show high-performance thermoelectric properties based on first-principles calculation. The crystal structure of these compounds belongs to the tetragonal P4/nmm space group (No. 129) at room temperature. The lattice parameter c decreases with increasing x, while a remains almost unchanged among the samples. Despite isovalent substitution of As for Sb, electrical resistivity significantly rises with increasing x. Very low thermal cond…
Spin-dependent Seebeck effect and huge growth of thermoelectric parameters at band edges in H- and F-doped graphene, free-standing and deposited on 4H-SiC(0001) C-face
The stability, electronic structure, optical and thermoelectric properties of Te-doped BaTiO3 are investigated by first-principal calculation based on the density functional theory and Boltzmann transport theory implemented in WIEN2K and BoltzTraP simulation program. This study is carried out by applying LDA + TB-mBJ potential. Formation energy of each doped structure is calculated to examine the stability and feasibility of the synthesis. Incorporating Te into BaTiO3 efficiently reduces the electronic band gap and the level of band gap reduction can be controlled by varying the amount of dopa…
Solid-state thermoelectric cooling is expected to be widely used in various cryogenic applications such as local cooling of superconducting devices. At present, however, thermoelectric cooling using p- and n-type Bi2Te3-based materials has been put to practical use only at room temperature. Recently, M4SiTe4 (M = Ta, Nb) has been found to show excellent n-type thermoelectric properties down to 50 K. This paper reports on the synthesis of high-performance p-type M4SiTe4 by Ti doping, which can be combined with n-type M4SiTe4 in a cooling device at low temperatures. The thermoelectric power fact…
Excellent thermoelectric performance in the out-of-layer n-doped SnSe has been observed experimentally (Chang et al., Science 360, 778-783 (2018)). However, a first-principles investigation of the dominant scattering mechanisms governing all thermoelectric transport properties is lacking. In the present work, by applying extensive first-principles calculations of electron-phonon coupling associated with the calculation of the scattering by ionized impurities, we investigate the reasons behind the superior figure of merit as well as the enhancement of zT above 600 K in n-doped out-of-layer SnSe…
How bilayer excitons can greatly enhance thermoelectric efficiency
目前，纳米技术的主要挑战之一是设计具有高品质因数的热电器件。为此，我们建议使用双层激子。双层激子系统示出具有改进的热电势和增强的电逆流和热导率，相对于常规的基于超导体的热电体。在这里，我们提出了一个双层激子热电偶的实验实现路线图。$p$和$n$掺杂的$_2$的双层激子异质结构可以具有品质因数$zT \sim 60$ .另一种材料建议是由电子掺杂的SrTiO $_3$和空穴掺杂的Ca $_3$ Co $_4$ O $_9$制成双层。
Thermoelectric and Magnetic Properties in Doped Fe$_2$VAl within a Bipolar Random Anderson Model
Department of Applied Physics, Tokyo University of Science（东京理科大学应用物理系）；Research Institute for Science and Technology, Tokyo University of Science（东京理科大学科学技术研究院）
Thermoelectric determination of electronic entropy change in Ni-doped FeRh
利用外加磁场下的低温热容实验，以及高温下的Seebeck效应和Hall系数测量，对Ni掺杂FeRh块状多晶中载流子的净熵变进行了实验研究.从热容数据中提取出电子熵变\(ΔS_{el}\approx8.9\) J\ kg \(^{-1}\) K \(^{-1}\)的值，而从塞贝克系数中获得高达4 J\ kg \(^{-1}\) K \(^{-1}\)的值。此外，塞贝克系数的分析允许跟踪的电子熵变化与所施加的磁场的演变。电子熵随外加磁场的增加而增加，在6 T时可达10%.
The power factor of pure p-type ZnSb has been calculated via ab initio simulations assuming that the carrier concentrations are due to the doping effect of intrinsic zinc vacancies. With a vacancy concentration close to the experimental solubility limit we were able to perfectly reproduce the Power Factor measured in polycrystalline ZnSb samples. The methodology has then been successfully extended for predicting the effect of extrinsic doping elements on the thermoelectric properties of ZnSb. Germanium and tin seem to be promising p-type doping elements. In addition, we give, for the first tim…
One-dimensional tellurides Ta4SiTe4 and Nb4SiTe4 were found to show high thermoelectric performance below room temperature. This study reported the synthesis and thermoelectric properties of whisker crystals of Ta4SiTe4-Nb4SiTe4 solid solutions and Mo- or Ti-doped (Ta0.5Nb0.5)4SiTe4. Thermoelectric power of the solid solutions systematically increased with increasing Ta content, while their electrical resistivity was unexpectedly small. Mo- and Ti-doped (Ta0.5Nb0.5)4SiTe4 showed n- and p-type thermoelectric properties with large power factors exceeding 40 microW cm-1 K-2, respectively. The fac…
Among layered oxygen-containing compounds, BiCuSeO is one of the most promising candidates for thermoelectric applications due to its intrinsically low thermal conductivity and good thermal stability. However, the rather poor electrical conductivity of pristine BiCuSeO hinders its potential. Further enhancement of the thermoelectric performance by single doping at Bi site is limited mainly due to dramatic decrease of carrier mobility. Thus, new strategies, such as dual doping or doping with variable-valence elements seem to be promising. Along with that, the development of a fast and scalable …
In this work, thermoelectric properties of Al$_{1.2}$Fe$_2$B$_2$ compound were investigated over a temperature range from 300\,K to 773\,K. Al$_{1.2}$Fe$_2$B$_2$ compound was produced by vacuum arc melting of Al, Fe, and B followed by annealing at 1323 K under argon atmosphere. The annealed ingots were subsequently crushed into powder and hot pressed at 1273 K under vacuum. The hot-pressed alloy predominantly contained Al$_{1.2}$Fe$_2$B$_2$ phase with a small fraction of FeB, which decreases further upon 0.1 \% Sb doping in Al$_{1.2}$Fe$_2$B$_2$. The pristine Al$_{1.2}$Fe$_2$B$_2$ exhibits n-t…
Electronic transport calculations for lightly-doped thermoelectrics using density functional theory: Application to high-performing Cu-doped zinc antimonides
We theoretically investigated the electronic, electrochemical and magnetic properties of Sb doped $Na_xCoO_2$ ($x = 1, 0.75$ and $0.50$). $Sb_{Co}$ dopants adopt +5 oxidation state in $Na_xCoO_2$ host lattice for all Na concentrations ($x$). Due to high oxidation states, $Sb^{5+}$ strongly repels Na ions and therefore it decreases the electrochemical potential (vs. Na/Na$^+$). The electrons introduced by $Sb^{5+}$ localize on nearby Co ions creating $Co^{2+}$ species which are absent in undoped $Na_xCoO_2$. $Co^{2+}$ ions reduce the spin entropy flow decreasing the Seebeck coefficient in the S…
Effect of Pb doping on the crystallization process and thermoelectric properties of Ge2Sb2Te5 phase change material
A.B. Nalbandyan Institute of Chemical Physics NAS RA（纳尔班扬化学物理研究所）；Belgorod State University（别尔哥罗德国立大学）；Institute of Radiophysics and Electronics NAS RA（无线电物理与电子研究所）
Thermoelectric transport properties of an apparent Fermi liquid: Relation to an analytic anomaly in the density of states and application to hole-doped delafossites
以最近发现的铜铁矿能带结构中的无色散区为动机，研究了一个包含不连续性作为分析反常的自由费米子态密度模型。由此产生的温度依赖性的化学势得到准确和不同的近似方案，然后进行了彻底的讨论。这包括引入一个近似的polylogarithmic差异，这是能够访问的参数范围既不涵盖索末菲展开，也不玻尔兹曼近似。它被发现，费米温度和其他几个温度标度可能是非常低的，从而引起实验观察到的行为不同于费米液体理论所描述的。特别是，两种明显的费米液体行为出现在中间温度。这种行为与最近报道的CuCr（1-x）MgxO 2 [A.迈尼昂等al，Solid State Commun. 149，962（2009）]和CuRh（1-x）MgxO 2 [A.迈尼昂等等人，Phys.Rev.B80，115103（2009）]通过温度无关的关联函数比率近似。以这种方式，确定这些材料的有效态密度以及有效载流子密度。此外，后者的材料的比热的结论得出的分析异常的特殊影响。
Diamond is one of the most studied materials because of its unique combination of remarkable electrical, mechanical, thermal and optical properties. Using a fully self-consistent ab initio theory of coupled electron-phonon transport, we reveal another striking behavior: a huge drag enhancement of the thermopower of lightly doped diamond. Thermopower values of around 100,000 microvolts per Kelvin are found at 100 K, significantly exceeding the highest previously measured value in the correlated metal FeSb2, and occurring at much higher temperatures. The enormous thermopower in diamond arises pr…
