Intrinsically Low Thermal Conductivity and High Carrier Mobility in Dual Topological Quantum Material, n‐Type BiTe

Abstract

A challenge in thermoelectrics is to achieve intrinsically low thermal conductivity in crystalline solids while maintaining a high carrier mobility (μ). Topological quantum materials, such as the topological insulator (TI) or topological crystalline insulator (TCI) can exhibit high μ. Weak topological insulators (WTI) are of interest because of their layered hetero‐structural nature which has a low lattice thermal conductivity (κlat). BiTe, a unique member of the (Bi2)m(Bi2Te3)n homologous series (m:n=1:2), has both the quantum states, TCI and WTI, which is distinct from the conventional strong TI, Bi2Te3 (where m:n=0:1). Herein, we report intrinsically low κlat of 0.47–0.8 W m−1 K−1 in the 300–650 K range in BiTe resulting from low energy optical phonon branches which originate primarily from the localized vibrations of Bi bilayer. It has high μ≈516 cm2 V−1 s−1 and 707 cm2 V−1 s−1 along parallel and perpendicular to the spark plasma sintering (SPS) directions, respectively, at room temperature.

Thickness-dependent properties of ultrathin bismuth and antimony chalcogenide films formed by physical vapor deposition and their application in thermoelectric generators

“…Experimental investigation of properties of nanostructured materials of the bismuth and antimony chalcogenide family also showed different results. For example, properties of nanostructured n-type BiTe showed coexistence of distinct topological quantum phases in this material resulting on potential decoupling of thermal and electronic transport properties, which is the fundamentals for efficient thermoelectrics [11].…”

Scale-invariant Machine-learning Model Accelerates the Discovery of Quaternary Chalcogenides with Ultralow Lattice Thermal Conductivity

“…The study of heat transport phenomena in materials is imperative to find and deploy suitable materials in various thermal-energy management platforms such as thermal barrier coatings [1], waste-heat recovery devices [2] and modern high-performance computing architectures which require rapid heat dissipation [3]. A sustained research effort in this direction has focused on finding materials with extreme thermal transport properties [3][4][5][6][7][8]. Among them, semiconducting materials with very low lattice thermal conductivity (κ l ) are particularly interesting as they find applications in thermoelectrics (TEs) which can convert heat into electrical energy [9][10][11].…”

Ultrafast scattering dynamics of coherent phonons in Bi$_{1-x}$Sb$_{x}$ in the Weyl semimetal phase

“…In the past decade, topological materials, such as topological insulators (TIs), Dirac semimetals, and Weyl semimetals, have attracted much attention in condensed matter physics owing to growing interest in the fundamental properties of their surface (bulk) band structure [1,2,3,4,5], massless quasiparticle dynamics [6], spin dynamics [2,7], carrier transport [8], and many other new physical effects [9,10,11,12]. Topological materials, in particular TIs, have been considered also as promising materials for thermoelectric devices, taking advantage of their intriguing properties, such as low thermal conductivities [13], and large Seebeck coefficients [14]. Bi 1−x Sb x was first experimentally discovered to be a 3D TI in 2008 (Ref.…”