Lattice Softening and Band Convergence in GeTe-Based Alloys for High Thermoelectric Performance.

GeTe-based alloys have been studied as promising TE materials in the midtemperature range as a lead-free alternate to PbTe due to their nontoxicity. Our previous study on GeTeI revealed that I-doping increases lattice anharmonicity and decreases the structural phase transition temperature, consequently enhancing the thermoelectric performance. Our current work elucidates the synergistic interplay between band convergence and lattice softening, resulting in an enhanced thermoelectric performance for GeSbTeI ( = 0.

Multiple magnetic transition and magnetocaloric properties in the mixed valence EuCuNiSi type I clathrate compound.

We investigated the magnetocaloric and electrical transport properties of the EuCuNiSi clathrate compound, synthesized by an arc melting and annealing method. X-ray photoemission spectroscopy revealed a mixed valence state of Eu and Eu. The low-field and low-temperature magnetic measurements indicated a multiple magnetic transition, from ferromagnetic near 35 K to antiferromagnetic at 25 K.

Single crystal synthesis and physical property of BaCuNiGaSi clathrate.

This study reports the synthesis of type-I BaCuNiGaSi clathrate as a single crystal by the flux method and physical properties investigations such as structural, chemical, magnetic, and thermal properties. Structural refinements indicate Ba atoms are situated at 2a and 6d positions with mixed occupancy across framework sites. Raman spectroscopy assessed host-guest interactions, while the compound's morphology and composition were investigated by the scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analyses.

Hierarchical Phonon Scattering from Nano to Macro Scale in Ag-Nano/TiO-Micro Particle-Decorated p-type Bismuth Telluride Bulk Composites.

We study the thermoelectric properties of a p-type BiSbTe (BST) composite with Ag nanoparticle-decorated TiO microparticles (US-Ag/TiO). The dispersion of US-Ag/TiO particles, synthesized by an ultrasonication (US) method, into the matrix effectively decreases lattice and bipolar thermal conductivity, attributed to the scattering centers formed at nano and micro scales. The electron backscattering diffraction (EBSD) measurements revealed smaller grain sizes within the BST composite when paired with the US-Ag/TiO particle dispersion.

Anisotropic Metamagnetic Spin Reorientation and Rotational Magnetocaloric Effect of Single Crystal NdAlGe.

Magnetic anisotropy strongly influences the performance of the magnetocaloric effect. We investigated the magnetocaloric properties of the NdAlGe single crystal with I4md structure. The temperature-dependent magnetization revealed significant anisotropic properties; stable antiferromagnetic transition at = 6 K for //a and meta-magnetic spin reorientation at low temperature ( ≤ 5 K) within an intermediate field ( = 2 T) for //c.

High critical current density and high-tolerance superconductivity in high-entropy alloy thin films.

High-entropy alloy (HEA) superconductors-a new class of functional materials-can be utilized stably under extreme conditions, such as in space environments, owing to their high mechanical hardness and excellent irradiation tolerance. However, the feasibility of practical applications of HEA superconductors has not yet been demonstrated because the critical current density (J) for HEA superconductors has not yet been adequately characterized. Here, we report the fabrication of high-quality superconducting (SC) thin films of Ta-Nb-Hf-Zr-Ti HEAs via a pulsed laser deposition.

An overview of synthetic methods and applications of photoluminescence properties of carbon quantum dots.

Carbon quantum dots (CQDs) are promising carbonaceous nanomaterials fortuitously discovered in 2004. CQDs are the rising stars in the nanotechnology ensemble because of their unique properties and widespread applications in sensing, imaging, medicine, catalysis, and optoelectronics. CQDs are notable for their excellent solubility and effective luminescence and, as a result, they are also known as carbon nanolights.

Weak antilocalization, spin-orbit interaction, and phase coherence length of a Dirac semimetal BiSb.

The present study develops a general framework for weak antilocalization (WAL) in a three-dimensional (3D) system, which can be applied for a consistent description of longitudinal resistivity [Formula: see text] and Hall resistivity [Formula: see text] over a wide temperature (T) range. Compared to the previous approach Vu et al. (Phys Rev B 100:125162, 2019), which assumes infinite phase coherence length (l) and a zero spin-orbit scattering length (l), the present framework is more general, covering high T and the intermediate spin-orbit coupling strength.

Development of High-Performance Thermoelectric Materials by Microstructure Control of P-Type BiSbTe Based Alloys Fabricated by Water Atomization.

Developing inexpensive and rapid fabrication methods for high efficiency thermoelectric alloys is a crucial challenge for the thermoelectric industry, especially for energy conversion applications. Here, we fabricated large amounts of p-type CuBiSbTe alloys, using water atomization to control its microstructure and improve thermoelectric performance by optimizing its initial powder size. All the water atomized powders were sieved with different aperture sizes, of 32-75 μm, 75-125 μm, 125-200 μm, and <200 μm, and subsequently consolidated using hot pressing at 490 °C.

Phonon Scattering and Suppression of Bipolar Effect in MgO/VO Nanoparticle Dispersed p-Type BiSbTe Composites.

Bismuth-Telluride-based compounds are unique materials for thermoelectric cooling applications. Because BiTe is a narrow gap semiconductor, the bipolar diffusion effect is a critical issue to enhance thermoelectric performance. Here, we report the significant reduction of thermal conductivity by decreasing lattice and bipolar thermal conductivity in extrinsic phase mixing of MgO and VO nanoparticles in BiSbTe (BST) bulk matrix.

Synergistic Enhancement of Thermoelectric Performances by Cl-Doping and Pb-Excess in (Pb,Sn)Se Topological Crystal Insulator.

We investigated the thermoelectric properties of the PbSnSe and PbSnSeCl (x = 0.0, 0.2, 0.

Scattering Mechanisms and Suppression of Bipolar Diffusion Effect in BiTeSeI Compounds.

We investigated the anisotropic thermoelectric properties of the BiTeSeI (x = 0.0, 0.1, 0.

Thermoelectric Properties and Low-Energy Carrier Filtering by Mo Microparticle Dispersion in an n-Type (CuI)Bi(Te,Se) Bulk Matrix.

We investigate the thermoelectric properties of (CuI)BiTeSe/Mo (Mo: 0.0, 0.9, 1.

Size-Controlled Au-CuSe Core-Shell Nanoparticles and Their Thermoelectric Properties.

One promising approach to improving thermoelectric energy conversion is to use nanostructured interfaces that enhance Seebeck coefficient while reducing thermal conductivity. Here, we synthesized Au-CuSe core-shell nanoparticles with different shell thicknesses by controlling the precursor concentration in solution. The Au-CuSe core-shell nanoparticles are about 37-53 nm in size, and the cores of the nanostructures are composed of Au nanoparticles with sizes of ∼11 nm.

Possible Charge Density Wave and Enhancement of Thermoelectric Properties at Mild-Temperature Range in n-Type CuI-Doped BiTeSe Compounds.

BiTe-based compounds have long been studied as thermoelectric materials in cooling applications near room temperature. Here, we investigated the thermoelectric properties of CuI-doped BiTeSe compounds. The Cu/I codoping induces the lattice distortion partially in the matrix.

Exotic Low-Energy Excitations Emergent in the Random Kitaev Magnet Cu_{2}IrO_{3}.

We report on magnetization M(H), dc and ac magnetic susceptibility χ(T), specific heat C_{m}(T) and muon spin relaxation (μSR) measurements of the Kitaev honeycomb iridate Cu_{2}IrO_{3} with quenched disorder. In spite of the chemical disorders, we find no indication of spin glass down to 260 mK from the C_{m}(T) and μSR data. Furthermore, a persistent spin dynamics observed by the zero-field muon spin relaxation evidences an absence of static magnetism.

Synergetic Enhancement of Thermoelectric Performance by Selective Charge Anderson Localization-Delocalization Transition in n-Type Bi-Doped PbTe/AgTe Nanocomposite.

Considerable efforts have been devoted to enhancing thermoelectric performance, by employing phonon scattering from nanostructural architecture, and material design using phonon-glass and electron-crystal concepts. The nanostructural approach helps to lower thermal conductivity but has limited effect on the power factor. Here, we demonstrate selective charge Anderson localization as a route to maximize the Seebeck coefficient while simultaneously preserving high electrical conductivity and lowering the lattice thermal conductivity.

Enhancement of thermoelectric properties over a wide temperature range by lattice disorder and chemical potential tuning in a (CuI) (BiTe) (BiSe) (BiS) quaternary system.

BiTe-based compounds have received attention as thermoelectric materials for room-temperature cooling and waste heat recovery applications. With potential application prospects, quaternary compounds of BiTe-BiSe-BiS composites can be used for mid-temperature power generation under 500 °C. Herein, we investigated the thermoelectric properties of (CuI) (BiTe) (BiSe) (BiS) ( = 0.

Enhancement of Thermoelectric Performance in Na-Doped PbSnTeSe S via Breaking the Inversion Symmetry, Band Convergence, and Nanostructuring by Multiple Elements Doping.

Topological insulators have attracted much interest in topological states of matter featuring unusual electrical conduction behaviors. It has been recently reported that a topological crystalline insulator could exhibit a high thermoelectric performance by breaking its crystal symmetry via chemical doping. Here, we investigate the multiple effects of Na, Se, and S alloying on thermoelectric properties of a topological crystalline insulator PbSnTe.

Enhancement of Thermoelectric Performances in a Topological Crystal Insulator PbSnSe via Weak Perturbation of the Topological State and Chemical Potential Tuning by Chlorine Doping.

Topological insulators generally share commonalities with good thermoelectric (TE) materials because of their narrow band gaps and heavy constituent elements. Here, we propose that a topological crystalline insulator (TCI) could exhibit a high TE performance by breaking its crystalline symmetry and tuning the chemical potential by elemental doping. As a candidate material, we investigate the TE properties of the Cl-doped TCI PbSnSe.

Interstitial Mo-Assisted Photovoltaic Effect in Multilayer MoSe Phototransistors.

Thin-film transistors (TFTs) based on multilayer molybdenum diselenide (MoSe ) synthesized by modified atmospheric pressure chemical vapor deposition (APCVD) exhibit outstanding photoresponsivity (103.1 A W ), while it is generally believed that optical response of multilayer transition metal dichalcogenides (TMDs) is significantly limited due to their indirect bandgap and inefficient photoexcitation process. Here, the fundamental origin of such a high photoresponsivity in the synthesized multilayer MoSe TFTs is sought.

Dataset on the electronic and thermal transport properties of quaternary compounds of (PbTe)(PbSe)(PbS).

The data presented in this article are related to the research article entitled "High thermoelectric performance in pseudo quaternary compounds of (PbTe) (PbSe)(PbS) by simultaneous band convergence and nano precipitation" (Ginting et al., 2017) [1]. We measured electrical and thermal transport properties such as temperature-dependent Hall carrier density , Hall mobility , thermal diffusivity , heat capacity , and power factor in (PbTe) (PbSe)(PbS) (=0.

High-Mobility Transistors Based on Large-Area and Highly Crystalline CVD-Grown MoSe2 Films on Insulating Substrates.

Large-area and highly crystalline CVD-grown multilayer MoSe2 films exhibit a well-defined crystal structure (2H phase) and large grains reaching several hundred micrometers. Multilayer MoSe2 transistors exhibit high mobility up to 121 cm(2) V(-1) s(-1) and excellent mechanical stability. These results suggest that high mobility materials will be indispensable for various future applications such as high-resolution displays and human-centric soft electronics.

Chemical Potential Tuning and Enhancement of Thermoelectric Properties in Indium Selenides.

Researchers have long been searching for the materials to enhance thermoelectric performance in terms of nano scale approach in order to realize phonon-glass-electron-crystal and quantum confinement effects. Peierls distortion can be a pathway to enhance thermoelectric figure-of-merit by employing natural nano-wire-like electronic and thermal transport. The phonon-softening known as Kohn anomaly, and Peierls lattice distortion decrease phonon energy and increase phonon scattering, respectively, and, as a result, they lower thermal conductivity.

Thermoelectric properties and chlorine doping effect of In4Pb0.01Sn0.03Se2.9Clx polycrystalline compounds.

We investigated the thermoelectric properties of Cl-doped polycrystalline compounds In4Pb0.01Sn0.03Se2.