Evaporated Metallic Contacts to Conducting Strontium Titanate Single Crystals

Carnes, J. E.; Goodman, Alvin M.

doi:10.1063/1.1710068

Cited by 32 publications

(10 citation statements)

References 11 publications

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“…31 Of most relevance to this work, STO also displays fascinating, and potentially useful, electronic transport properties. The material is a semiconductor with a 3.2 eV band gap 1, 32 and can be doped n type [32][33][34][35][36][37][38][39][40][41][42][43][44] or p type. [45][46][47][48][49][50][51] n-type conduction has been most commonly achieved by substitution of La 3+ for Sr 2+ ͑i.e., Sr 1−x La x TiO 3 ͒, 1,33,34 Nb 5+ for Ti 4+ ͑i.e., SrTi 1−y Nb y O 3 ͒, [35][36][37] or by reduction to SrTiO 3−␦ , 32,35,[38][39][40][41][42][43][44] where, in a simple picture, each O vacancy generates two doped electrons.…”

Section: Introductionmentioning

confidence: 99%

Electronic transport in dopedSrTiO3: Conduction mechanisms and potential applications

et al. 2010

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Resistivity, Hall effect, and magnetoresistance are reported on a large set of semiconducting SrTiO 3−␦ single crystals doped n-type ͑by reduction or Nb substitution͒ over a broad range of carrier density ͑the 10 15 to mid 10 20 cm −3 range͒. Temperature-independent carrier densities, strongly temperature-dependent mobilities ͑up to 22 000 cm 2 V −1 s −1 at 4.2 K͒, and a remarkably low critical carrier density for the metal-insulator transition are observed, and interpreted in terms of the known quantum paraelectricity of the host. We argue that an unusual, high mobility, low density, metallic state is thus established at carrier densities at least as low as 8.5ϫ 10 15 cm −3 , in contrast to some prior conclusions. At low temperatures, the temperature dependence of the mobility and resistivity exhibit a nonmonotonic carrier density dependence and an abrupt change in character near 2 ϫ 10 16 cm −3 , indicating a distinct crossover in conduction mechanism, perhaps associated with a transition from impurity-band to conduction-band transport. The results provide a simple framework for the understanding of the global transport behavior of doped SrTiO 3 . Finally, it is proposed that the large residual resistivity ratios ͑Ͼ3000͒, and large, temperature independent, Hall coefficients ͑Ͼ1700 cm 3 C −1 ͒, demonstrate considerable potential for high-sensitivity resistive thermometry and Hall sensing applications.

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Section: Introductionmentioning

confidence: 99%

Electronic transport in dopedSrTiO3: Conduction mechanisms and potential applications

et al. 2010

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“…2 When a metal electrode is deposited on a carrier-doped perovskite oxide, a potential barrier, called the Schottky barrier, is formed at the interface which characterizes the electrical properties of the junctions. 5,6 Since the electrical prop-erties of the Schottky junction in general are very sensitive to interface electronic states, 7 a suitable formation technique for a well-controlled metal/STO junction is essential to clear out intrinsic natures of the electrical properties of the metal/STO interface. Understanding of intrinsic natures of the metal/ STO interface is of great interest in both science and technology of the interface of the transition metal oxides, because the STO is one of the most attractive materials for catalysts, 8 dielectrics, 9 superconductors, 10 and strong electron correlation systems.…”

Section: Introductionmentioning

confidence: 99%

Intrinsic electrical properties of Au/SrTiO3 Schottky junctions

Shimizu¹,

Okushi²

1999

Journal of Applied Physics

100

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Intrinsic electrical properties of Au/Nb-doped SrTiO 3 ͑001͒ ͑STO:Nb͒ Schottky junctions, fabricated using a proper surface treatment of the STO:Nb and in situ deposition of Au, were investigated in detail. Current-voltage characteristics and photocurrent-wavelength characteristics have shown a temperature-dependent and voltage-dependent Schottky barrier height, while capacitance-voltage characteristics have shown a temperature-independent flat band voltage. Using a temperature-dependent and field-dependent permittivity of the STO in the framework of Devonshire theory, we have performed computer simulation of the Schottky barrier potential to analyze the electrical properties of the junction. It is found that an intrinsic low permittivity layer at the Au/STO:Nb interface explains all the temperature dependence of the electrical properties.

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“…6 Electron-doped SrTiO 3 has long been used as a semiconducting element in rectifying junctions. 7,8 Oxygen vacancies, as well as substitutional doping such as Nb on the Ti-site in SrTiO 3 , generate conduction electrons. 9 Recently, diode characteristics have been demonstrated in manganite-titanate junctions, [10][11][12][13] where the manganite hole concentration was initially minimized to resemble semiconductor p-i-n or p-n junctions, corresponding to bulk insulating concentrations.…”

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confidence: 99%

Magnetocapacitance and exponential magnetoresistance in manganite–titanate heterojunctions

Nakagawa

Asai

Mukunoki

et al. 2005

Applied Physics Letters

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We present a rectifying manganite-titanate heterojunction exhibiting a magnetic field tunable depletion layer. This creates a large positive magnetocapacitance, a direct measure of the fieldinduced reduction of the effective depletion width across the junction. Furthermore, the reduction of the junction barrier shifts the forward bias characteristics, giving exponentially-enhanced differential magnetoresistance, occurring despite the absence of a spin filter. These results provide a unique probe of a Mott insulator/band insulator interface, and further suggest new electronic devices incorporating the magnetic field sensitivity of these strongly correlated electron materials. PACS numbers: 75.70.Cn, 75.47.Lx, 73.40.Ei 1 There is a continual search for new methods and materials to utilize magnetic response in electronic devices, ranging from dilute magnetic semiconductors, 1 metal superlattices, 2 magnetic oxides, 3 as well as hybrid structures among them. Perovskite manganites exhibit strong electronspin coupling, manifesting dramatic magnetoresistance near the simultaneous magnetic and metal-insulator transition, 3 as well as a fully spin-polarized ground state. 4 The later feature has been explored in spin-polarized transport at grain boundaries 5 and thin film tunnel junctions. 6 Electron-doped SrTiO 3 has long been used as a semiconducting element in rectifying junctions. 7,8 Oxygen vacancies, as well as substitutional doping such as Nb on the Ti-site in SrTiO 3 , generate conduction electrons. 9 Recently, diode characteristics have been demonstrated in manganite-titanate junctions, 10-13 where the manganite hole concentration was initially minimized to resemble semiconductor p-i-n or p-n junctions, corresponding to bulk insulating concentrations. Ferromagnetic metallic manganites are formed by doping holes in the antiferromagnetic Mott insulator LaMnO 3 , with the metal-insulator transition occurring for ~ 17 % hole doping in La 1-x Sr x MnO 3 . 3 We have found that rectification can be observed even for much higher hole concentrations, and focus here on junctions using La 0.7 Sr 0.3 MnO 3-δ to vary across the ferromagnetic state. For La 0.7 Sr 0.3 MnO 3-δ /Nb:SrTiO 3 junctions, we find a significant increase in the junction capacitance in an applied magnetic field. Corresponding to this decrease in the depletion width, the reduction of the current barrier gives rise to exponential differential magnetoresistance. The modification of the electronic structure at the heterointerface by magnetic field is enabled by the unusual features arising from strong charge-spin coupling, giving a direct probe of the correlated electron equivalent of semiconductor band bending.

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Evaporated Metallic Contacts to Conducting Strontium Titanate Single Crystals

Cited by 32 publications

References 11 publications

Electronic transport in dopedSrTiO3: Conduction mechanisms and potential applications

Electronic transport in dopedSrTiO3: Conduction mechanisms and potential applications

Intrinsic electrical properties of Au/SrTiO3 Schottky junctions

Magnetocapacitance and exponential magnetoresistance in manganite–titanate heterojunctions

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