1. Cahill, D. G., Watson, S. K. & Pohl, R. O. Lower limit to the thermal conductivity of disordered crystals. Phys. Rev. B 46, 6131–6140 (1992).

2. Dresselhaus, M. et al. New directions for low-dimensional thermoelectric materials. Adv. Mater. 19, 1043–1053 (2007).

3. Koumoto, K. & Mori, T. (eds) Thermoelectric Nanomaterials (Springer, 2013).

4. Graf, T., Felser, C. & Parkin, S. S. Simple rules for the understanding of Heusler compounds. Prog. Solid State Chem. 39, 1–50 (2011).

5. Felser, C. & Hirohata, A. (eds) Heusler Alloys: Properties, Growth, Applications (Springer, 2016).

6. Knapp, I. et al. Impurity band effects on transport and thermoelectric properties of Fe 2−x Ni x VAl. Phys. Rev. B 96, 045204 (2017).

7. Venkatasubramanian, R., Siivola, E., Colpitts, T. & O’Quinn, B. Thin-film thermoelectric devices with high room-temperature figures of merit. Nature 413, 597–602 (2001).

8. Zhao, L.-D. et al. Ultralow thermal conductivity and high thermoelectric figure of merit in SnSe crystals. Nature 508, 373–377 (2014).

9. Zhang, H. & Talapin, D. V. Thermoelectric tin selenide: the beauty of simplicity. Angew. Chem. 53, 9126–9127 (2014).

10. Tan, G. et al. Non-equilibrium processing leads to record high thermoelectric figure of merit in PbTe–SrTe. Nat. Commun. 7, 12167 (2016).

11. Mori, T. Novel principles and nanostructuring methods for enhanced thermoelectrics. Small 13, 1702013 (2017).

12. Chen, Y.-T. & Tan, Y. The optical, magnetic, and electrical characteristics of Fe 2 Si thin films. J. Alloys Compd. 615, 946–949 (2014).

13. Tang, C. P., Tam, K. V., Xiong, S. J., Cao, J. & Zhang, X. The structure and electronic properties of hexagonal Fe 2 Si. AIP Adv. 6, 065317 (2016).

14. Yordanov, P. et al. Perovskite substrates boost the thermopower of cobaltate thin films at high temperatures. Appl. Phys. Lett. 110, 253101 (2017).

15. Wong, D. High power factor Ge-Sb-Te thermoelectric thin film: an evidence of temperature-induced band convergence. In 37th Int. Conference on Thermoelectrics (ICT, 2018).

16. Cha, J., Zhou, C., Cho, S.-P., Park, S. H. & Chung, I. Ultrahigh power factor and electron mobility in n-type Bi 2 Te 3–x% Cu stabilized under excess Te condition. ACS Appl. Mater. Interfaces 11, 30999–31008 (2019).

17. Hazama, H. et al. Improvement of power factor of n-type Bi 2 Te 3 by dispersed nanosized Ga 2 Te 3 precipitates. J. Alloys Compd. 726, 578–586 (2017).

18. Baba, T., Taketoshi, N. & Yagi, T. Development of ultrafast laser flash methods for measuring thermophysical properties of thin films and boundary thermal resistances. Jpn. J. Appl. Phys. 50, 11RA01 (2011).

19. Baba, T. Analysis of one-dimensional heat diffusion after light pulse heating by the response function method. Jpn. J. Appl. Phys. 48, 05EB04 (2009).

20. Hinterleitner, B. et al. Stoichiometric and off-stoichiometric full Heusler Fe 2 V 1-x W x Al thermoelectric systems. Preprint at https://arxiv.org/abs/1801.08966 (2018).

21. Petsagkourakis, I. et al. Thermoelectric materials and applications for energy harvesting power generation. Sci. Technol. Adv. Mater. 19, 836–862 (2018).

22. Burkov, A. A., Hook, M. D. & Balents, L. Topological nodal semimetals. Phys. Rev. B 84, 235126 (2011).

23. Li, R. et al. Dirac node lines in pure alkali earth metals. Phys. Rev. Lett. 117, 096401 (2016).

24. Lv, B. Q. et al. Experimental discovery of Weyl semimetal TaAs. Phys. Rev. X 5, 031013 (2015).

25. Weng, H., Fang, C., Fang, Z., Bernevig, B. A. & Dai, X. Weyl semimetal phase in noncentrosymmetric transition-metal monophosphides. Phys. Rev. X 5, 011029 (2015).

26. Xu, N., Xu, Y. & Zhu, J. Topological insulators for thermoelectrics. npj Quant. Mater. 2, 51 (2017).

27. Tang, Y. et al. Convergence of multi-valley bands as the electronic origin of high thermoelectric performance in CoSb3 skutterudites. Nat. Mater. 14, 1223–1228 (2015).

28. Zeier, W. G. et al. Thinking like a chemist: intuition in thermoelectric materials. Angew. Chem. 55, 6826–6841 (2016).

29. Zhang, J. et al. Discovery of high-performance low-cost n-type Mg 3 Sb 2 -based thermoelectric materials with multi-valley conduction bands. Nat. Commun. 8, 13901 (2017).

30. Baba, T. et al. Research and development of metrological standards for thermophysical properties of solids in the National Metrology Institute of Japan. High Temp. High Press. 39, 279–306 (2010).

31. Yagi, T., Taketoshi, N. & Baba, T. Development of thin film reference material for thermal diffusivity. In Proc. 1st Int. Symposium on Thermal Design and Thermophysical Property for Electronics (NMIJ/AIST, 2008).

32. Hohenberg, P. & Kohn, W. Inhomogeneous electron gas. Phys. Rev. 136, B864–B871 (1964).

33. Kohn, W. & Sham, L. J. Self-consistent equations including exchange and correlation effects. Phys. Rev. 140, A1133–A1138 (1965).

34. Kresse, G. & Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 47, 558–561 (1993).

35. Kresse, G. & Hafner, J. Ab initio molecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Phys. Rev. B 49, 14251–14269 (1994).

36. Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).

37. Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).

38. Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).

39. Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

40. Eckhardt, C., Hummer, K. & Kresse, G. Indirect-to-direct gap transition in strained and unstrained Sn x Ge 1−x alloys. Phys. Rev. B 89, 165201 (2014).

41. Liu, P. et al. Electron and hole doping in the relativistic mott insulator Sr 2 IrO 4 : a first-principles study using band unfolding technique. Phys. Rev. B 94, 195145 (2016).

42. Massalski, T. B. Binary Alloy Phase Diagrams (ASM International, 1990).

43. Dugdale, J. The Electrical Properties of Metals and Alloys (Dover, 2016).

44. Yu, C., Scullin, M. L., Huijben, M., Ramesh, R. & Majumdar, A. Thermal conductivity reduction in oxygen-deficient strontium titanates. Appl. Phys. Lett. 92, 191911 (2008).

45. Koga, T., Cronin, S. B., Dresselhaus, M. S., Liu, J. L. & Wang, K. L. Experimental proof-of-principle investigation of enhanced Z 3D T in (001) oriented Si/Ge superlattices. Appl. Phys. Lett. 77, 1490–1492 (2000).

46. Heinze, S. et al. Thermoelectric properties of YBa 2 Cu 3 O 7−δ –La 2/3 Ca 1/3 MnO 3 superlattices. Appl. Phys. Lett. 101, 131603 (2012).

47. Chambers, R. G. The two-band effect in conduction. Proc. Phys. Soc. A 65, 903–910 (1952).

48. Arushanov, E. K. & Chuiko, G. P. The magnetic field dependence of kinetic coefficients of cadmium arsenide single crystals. Phys. Status Solidi A 17, K135–K138 (1973).

49. Eguchi, G. & Paschen, S. Robust scheme for magnetotransport analysis in topological insulators. Phys. Rev. B 99, 165128 (2019).

50. Jensen, J. E., Tuttle, W. A., Stewart, R. B., Brechna, H. & Prodell, A. G. (eds) Brookhaven National Laboratory Selected Cryogenic Data Notebook. Report BNL-10200-R (Brookhaven National Laboratory, 1980).

51. Furuta, Y., Kato, K., Miyawaki, T., Asano, H. & Takeuchi, T. Fe 2 VAl-based thermoelectric thin films prepared by a sputtering technique. J. Electron. Mater. 43, 2157–2164 (2014).

52. Tsai, M.-H. Physical properties of high entropy alloys. Entropy 15, 5338–5345 (2013).

53. Cahill, D. G. et al. Nanoscale thermal transport. J. Appl. Phys. 93, 793–818 (2003).

54. Baba, T., Ishikawa, K. & Baba, T. Analysis of heat diffusion in thin films and boundary resistance by pulsed light heating thermoreflectance method. In 3rd Int. Conference on Functional Integrated NanoSystems (NanoFis, 2017).

55. Baba, T., Ishikawa, K. & Baba, T. Measurement and analysis of thermal conductivity, thermal diffusivity and interfacial thermal resistance of thermoelectric thin films. In 37th Int. Conference on Thermoelectrics (ICT, 2018).

56. Goldsmid, H. J. & Sharp, J. W. Estimation of the thermal band gap of a semiconductor from Seebeck measurements. J. Electron. Mater. 28, 869–872 (1999).

57. Lue, C. S., Ross, J. H., Chang, C. F. & Yang, H. D. Field-dependent specific heat in Fe 2 VAl and the question of possible 3d heavy fermion behavior. Phys. Rev. B 60, R13941–R13945 (1999).

58. Wang, G., Endicott, L. & Chi, H. Lošt’ák, P. & Uher, C. Tuning the temperature domain of phonon drag in thin films by the choice of substrate. Phys. Rev. Lett. 111, 046803 (2013).

59. Zhao, W. et al. Superparamagnetic enhancement of thermoelectric performance. Nature 549, 247–251 (2017).