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The properties that distinguish topologicalcrystalline insulator (TCI) and topological insulator (TI) rely oncrystalline symmetry and time-reversal symmetry, respectively, whichencodes different bulk and surface/edge properties. Here, we predicttheoretically that electron-doped TlM (M = S and Se) (110) monolayersrealize a family of two-dimensional (2D) TCIs characterized by mirrorChern number CM= −2. Remarkably,under uniaxial strain (≈ 1%), a topological phase transitionbetween 2D TCI and 2D TI is revealed with the calculated spin Chernnumber CS= −1 for the 2D TI. Usingspin-resolved edge states analysis, we show different edge-state behaviors,especially at the time reversal invariant points. Finally, a TlBiSe2/NaCl quantum well is proposed to realize an undoped 2D TCIwith inverted gap as large as 0.37 eV, indicating the high possibilityfor room-temperature observation. [ABSTRACT FROM AUTHOR]

Spin caloric transport refers to the coupling of heat with spin transport. Its applications primarily concern the generation of spin currents and control of magnetisation by temperature gradients for information technology, known by the synonym spin caloritronics. Within the framework of ab initio theory, new tools are being developed to provide an additional understanding of these phenomena in realistic materials, accounting for the complexity of the electronic structure without adjustable parameters. Here, we review this progress, summarising the principles of the density-functional-based approaches in the field and presenting a number of application highlights. Our discussion includes the three most frequently employed approaches to the problem, namely the Kubo, Boltzmann, and Landauer–Büttiker methods. These are showcased in specific examples that span, on the one hand, a wide range of materials, such as bulk metallic alloys, nano-structured metallic and tunnel junctions, or magnetic overlayers on heavy metals, and, on the other hand, a wide range of effects, such as the spin-Seebeck, magneto-Seebeck, and spin-Nernst effects, spin disorder, and the thermal spin-transfer and thermal spin–orbit torques. [ABSTRACT FROM AUTHOR]