weighted by cyclical constrains. Furthermore, the approach proposed by Schumpeter embodies another fundamental idea, which is the competition between innovators. Indeed, these players pursue the monopoly rents that accrue to new proprietary technologies, and, as such, intend to be the fi rst to fi nd the right solution to the right problem at the right moment. Economists have been studying the relationship between innovation and competition for many years, trying to understand more specifi cally whether competition fosters innovation or not. As a matter of fact, some concluded on a negative infl uence of competition upon innovation and some on a positive effect. [ 2,5 ] But it appears that many economists and marketers converge toward the idea that the innovation versus competition curve shows an inverted U shape. [ 6 ] In other words some competition is constructive, yet aggressive competition tends to hamper the innovation process.It is interesting to place in this context the concept of duplication. Historians and sociologist often refer to multiple discoveries for cases in which similar discoveries are made simultaneously by scientists working independently from each other. [ 7 ] The wide literature of scientifi c discovery can be classifi ed into three basic categories: [ 8 ] the genius model, [ 9 ] the model based on chance, [ 10 ] and the model relying on cultural maturation. [ 11 ] The latter type, which is the more prone to multiplicity, suggests that the contributions of individual researcher are epiphenomenal. This school of thought advocates the infl uence of social determinism and zeitgeist. [ 12 ] As a consequence, it proposes that the change in science is strongly infl uenced by cultural priorities and research programs. [ 8 ] This very type of duplication can be considered benefi cial for society as a higher number of independent experiments does maximize the probability of the accuracy and the reality of a given discovery. [ 11 ] This point of view is easily applicable to paradigm shifting, major discoveries, especially if they occurred before the era of easily accessible information via the internet, gigantic centralized databases, and ultrafast search engines. However, nowadays it may appear obvious that the replication of the effort to generate innovation is socially suboptimal and reduces the overall return on investment for entities that fi nance research. None of the studies mentioned above accounts for that phenomenon because of the diffi culty to quantify modern duplication. Thus, despite its acknowledged relevance [ 13 ] and occurrence, the share and infl uence of modern duplication in academic and industrial research remains largely underexplored. The European Patent Offi ce (EPO) affi rms that "up to 30% of all expenditure in R&D is wasted on redeveloping existing Copper sulfi des and copper selenides have recently been reported as new and promising low-cost and environmentally friendly thermoelectric materials. Here, it is shown that these materials have actually been studied for mo...

Sb2Te3 has recently been an object of intensive research since its promising applicability in thermoelectric, in phase-change memory devices and as a topological insulator. In this work we report highly textured Sb2Te3 thin films, grown by atomic layer deposition on Si/SiO2 wafers based on the reaction of SbCl3 and Te(SiMe3)2. The low deposition temperature at 80° C allows for the pre-patterning of the Sb2Te3 by standard lithography processes. A platform to characterize the Seebeck-coefficient S, the electrical conductivity σ as well as the Hall coefficient RH on the same film has been developed. Comparing all temperature-dependent transport properties, three different conductive regions in the temperature range of 75 to 300 K are found. Room temperature values of S = 146 V K -1 ,  = 10 4 S m -1 and mobility  = 270.5 x 10 4 m 3 V -1 s -1 are determined. The low carrier concentration in the range of n = 2.4 x 10 18 cm -3 at 300 K quantifies the low defect content of the Sb2Te3 thin films.

This work presents a comprehensive study of the fabrication and optimization of electrodeposited p‐ and n‐type thermoelectric films. The films are deposited on Au and stainless steel substrates over a wide range of deposition potentials. The influence of the preparative parameters such as the composition of the electrolyte bath and the deposition potential are investigated. Furthermore, the p‐doped (BixSb1‐x)2Te3 and the n‐doped Bi2(TexSe1‐x)3 films are annealed for a period of about 1 h under helium and under tellurium atmosphere at 250 °C for 60h. Annealing in He already leads to significant improvements in the thermoelectric performance. Furthermore, due to the equilibrium conditions during the process, annealing in Te atmosphere leads to a strongly improved film composition, charge carrier density and mobility. The Seebeck coefficients increase to values up to +182 μV K−1 for p‐doped and–130 μV K−1 for n‐doped materials at room temperature. The power factors also exhibit improvements with 1320 μW m−1 K−2 and 820 μW m−1 K−2 for p‐doped and n‐doped films, respectively. Additionally, in‐situ XRD measurements performed during annealing of the films up to 600K under He atmosphere show stepwise improvements of the crystal structure leading to the improvements in thermoelectric parameters. The thermal conductivity is between 1.2 W m−1 K−1 and 1.0 W m−1 K−1.

films were grown by a MOCVD process on Al 2 O 3 (0001) substrates at 400 C by use of i-Pr 3 Sb and Et 2 Te 2 and characterized by SEM, AFM, XRD, EDX and Auger spectroscopy. The electrical sheet resistivity was measured in the range of 4 to 400 K, showing a monotonic increase with increasing temperature. The valence band structure probed by angle-resolved photoemission shows the detailed dispersions of the bulk valence band and the topological surface state of a quality no less than for optimized bulk single crystals. The surface state dispersion gives a Dirac point roughly 30 meV above the Fermi level leading to hole doping and the presence of bulk valence states at the Fermi energy.

Ab initio electronic structure calculations based on density functional theory and tight-binding methods for the thermoelectric properties of ptype Sb 2 Te 3 films are presented. The thicknessdependent electrical conductivity and the thermopower are computed in the diffusive limit of transport based on the Boltzmann equation. Contributions of the bulk and the surface to the transport coefficients are separated which enables to identify a clear impact of the topological surface state on the thermoelectric properties. By tuning the charge carrier concentration, a crossover between a surface-state-dominant and a FuchsSondheimer transport regime is achieved. The calculations are corroborated by thermoelectric transport measurements on Sb 2 Te 3 films grown by atomic layer deposition.Almost all proposed three-dimensional (3D) Z 2 topological insulators (TIs) 1,2 are efficient thermoelectric materials. That is not by coincidence, since the link between an efficient thermoelectric * To whom correspondence should be addressed † Institute of Physics, Martin Luther University HalleWittenberg, D-06099 Halle, Germany ‡ Institute of Nanostructure and Solid State Physics, Universität Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany ¶ Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle, Germany material and the topological character is the inverted band gap. 3,4 The last is due to spin-orbit coupling which switches parity of the bands and leads, if strong enough, to narrow band gaps which are favourable for efficient room-temperature thermoelectrics. Usually strong spin-orbit coupling is mediated by heavy elements which in turn also tend to reduce the material's lattice thermal conductivity, another requirement for desirable thermoelectrics.In the early 90's, Hicks and Dresselhaus 5,6 proposed the concept of low-dimensionality to increase further the thermoelectric efficiency; primarily in thin films, the thermopower S should be enlarged. However, in contrast to previous theoretical model calculations, 7,8 decreased values of S were found experimentally 9-11 for Bi 2 Te 3 and Sb 2 Te 3 thin films and were recently corroborated by both model 12,13 and ab initio calculations 4 of our groups.Thus, to resolve this discrepancy, the potential impact of the surface state (SS) of TIs on thermoelectricity needs to be investigated in more detail. In this Letter, we present ab initio calculations and transport measurements of the thermoelectric properties of Sb 2 Te 3 films at varying thickness, temperature and charge carrier concentration. (1/ cm)(g) Theoretical resultsIn the following, we discuss the doping-and temperature-dependent electrical conductivity and thermopower, as shown in Fig. 1, exemplary for a Sb 2 Te 3 film thickness of 18 quintuple-layer (QL), i.e. about 18 nm. A discussion of films with other thicknesses is given in the supplemental material. 14 The converged electronic structure results serve as input to obtain the thermoelectric transport properties at temperature T and fixed extri...