Two-Dimensional Quantum Oscillations of the Conductance at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>LaAlO</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mi>SrTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>Interfaces

Caviglia, Andrea D.; Gariglio, Stefano; Cancellieri, Claudia; Sacépé, Benjamin; Fête, Alexandre; Reyren, Nicolas; Gabay, M.; Morpurgo, Alberto F.; Triscone, Jean‐Marc

doi:10.1103/physrevlett.105.236802

Cited by 257 publications

(312 citation statements)

References 27 publications

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“…Recently, there has been a mounting interest in 2DEG systems formed at epitaxially grown insulating metal oxide heterointerfaces12 due to the very high charge carrier mobilities13 and their potential for high‐performance electronics14, 15 as well as the rich new physics 16. Building on the early work on insulating oxides, Tampo et al17 demonstrated the formation of 2DEGs in semiconducting ZnO/MgZnO heterointerfaces for which electron mobilities exceeding 700 000 cm 2 V −1 s −1 , albeit at cryogenic temperatures, have recently been reported 18…”

Section: Introductionmentioning

confidence: 99%

High Electron Mobility Thin‐Film Transistors Based on Solution‐Processed Semiconducting Metal Oxide Heterojunctions and Quasi‐Superlattices

et al. 2015

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High mobility thin‐film transistor technologies that can be implemented using simple and inexpensive fabrication methods are in great demand because of their applicability in a wide range of emerging optoelectronics. Here, a novel concept of thin‐film transistors is reported that exploits the enhanced electron transport properties of low‐dimensional polycrystalline heterojunctions and quasi‐superlattices (QSLs) consisting of alternating layers of In2O3, Ga2O3, and ZnO grown by sequential spin casting of different precursors in air at low temperatures (180–200 °C). Optimized prototype QSL transistors exhibit band‐like transport with electron mobilities approximately a tenfold greater (25–45 cm2 V−1 s−1) than single oxide devices (typically 2–5 cm2 V−1 s−1). Based on temperature‐dependent electron transport and capacitance‐voltage measurements, it is argued that the enhanced performance arises from the presence of quasi 2D electron gas‐like systems formed at the carefully engineered oxide heterointerfaces. The QSL transistor concept proposed here can in principle extend to a range of other oxide material systems and deposition methods (sputtering, atomic layer deposition, spray pyrolysis, roll‐to‐roll, etc.) and can be seen as an extremely promising technology for application in next‐generation large area optoelectronics such as ultrahigh definition optical displays and large‐area microelectronics where high performance is a key requirement.

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Section: Introductionmentioning

confidence: 99%

High Electron Mobility Thin‐Film Transistors Based on Solution‐Processed Semiconducting Metal Oxide Heterojunctions and Quasi‐Superlattices

et al. 2015

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“…Furthermore, the obtained n SdH is lower than both n II , n I for this sample, so that it is not possible to associate the SdH oscillation to one specific channel. A discrepancy between n SdH and n Hall in LAO/STO interfaces has already been reported and its origin remains unknown [33,34].…”

mentioning

confidence: 98%

Insulator-to-Metal Transition at Oxide Interfaces Induced by WO₃ Overlayers

Mattoni

Baek²,

Manca

et al. 2017

ACS Appl. Mater. Interfaces

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Interfaces between complex oxides constitute a unique playground for 2D electron systems (2DES), where superconductivity and magnetism can arise from combinations of bulk insulators. The 2DES at the LaAlO 3 /SrTiO 3 interface is one of the most studied in this regard, and its origin is determined by both the presence of a polar field in LaAlO 3 and the insurgence of point defects, such as oxygen vacancies and intermixed cations. These defects usually reside in the conduction channel and are responsible for a decreased electronic mobility. In this work, we use an amorphous WO 3 overlayer to control the defect formation and obtain an increased electron mobility in WO 3 /LaAlO 3 /SrTiO 3 heterostructures. The studied system shows a sharp insulator-to-metal transition as a function of both LaAlO 3 and WO 3 layer thickness. Low-temperature magnetotransport reveals a strong magnetoresistance reaching 900% at 10 T and 1.5 K, the presence of multiple conduction channels with carrier mobility up to 80 000 cm 2 V −1 s −1 and an unusually high effective mass of 5.6 me. The amorphous character of the WO 3 overlayer makes this a versatile approach for defect control at oxide interfaces, which could be applied to other heterestrostures disregarding the constraints imposed by crystal symmetry.The formation of a two-dimensional electron system (2DES) at the interface between band insulators SrTiO 3 (STO) and LaAlO 3 (LAO) is among the most intriguing effects studied in oxide electronics [1]. Gate tunable superconductivity [2,3], strong spin-orbit coupling [4,5] and magnetism [6,7] are some of the many phenomena observed. The origin of this 2DES is a long standing question in the solid state community and recent results indicate that a consistent picture should take into account both the built-in polar field and the presence of point defects [8][9][10]. Among these, oxygen vacancies and cation off-stoichiometry in STO are capable of inducing a 2DES [11,12]. However, defects residing in the conductive channel are usually responsible for a decreased electronic mobility [13]. In order to promote high electron mobility, it is crucial to confine donor sites away from the conducting plane, without preventing the 2DES formation in the STO top layers. Previous attempts to control the defect concentration profile and thus enhance the mobility involved the use of crystalline insulating overlayers [14,15] [18,19]. A promising material to control defect formation is tungsten oxide WO 3 . The several possible oxidations states of tungsten make WO 3 particularly active in undergoing redox reactions. For this reason this material is often utilized in electrochemical applications and electrochromic devices [20][21][22]. Also, both crystalline and amorphous WO 3 can host vacancies and interstitial atoms, thus allowing cation accommodation and diffusion, with a tendency to form compounds such as tungsten bronzes [23,24]. Recent progress demonstrated the high-quality growth of WO 3 thin films on perovskite materials [25][26][27].In this work we co...

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“…Inter-sub-band scattering (a) quantized sub-bands [17,[22][23][24][25][26][27][28][29][30][31][32]. Thus a consistent understanding of both the normal and the superconducting states requires consideration of the sub-band structure in the electrostatic confinement potential which must be considered self-consistently throughout the system as a whole.…”

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confidence: 99%

Tunable coupling of two-dimensional superconductors in bilayer SrTiO3heterostructures

et al. 2013

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Interlayer coupling effects between high mobility two-dimensional superconductors are studied in bilayer δ-doped SrTiO3 heterostructures. By tuning the undoped SrTiO3 spacer layer between the dopant planes, clear tunable coupling is demonstrated in the variation of the sheet carrier density, Hall mobility, superconducting transition temperature, and the temperature-and angle-dependences of the superconducting upper critical field. Systematic variation is found between one effective (merged) two-dimensional superconductor to two decoupled two-dimensional superconductors. In the intermediate coupled regime, a crossover is observed due to coupling arising from inter-sub-band interactions.Interlayer coupling between two-dimensional (2D) planes in layered materials is a key parameter which dramatically influences their physics and functionality. Paradigmatic examples in the field of superconductivity include the high temperature superconducting cuprates [1, 2], and the iron pnictides [3], as well as artificially created superlattices, in which the Josephson coupling between the layers can be tunable continuously using thin film control [4,5]. There have also been extensive studies of coupled bilayer 2D systems, where exotic phases arise from the interlayer interactions [6][7][8][9][10][11][12].Among the various 2D systems currently under investigation, SrTiO 3 (STO) is of particular interest since it is a rare example of a high mobility doped semiconductor that is simultaneously superconducting. By confining electrons in STO two-dimensionally using field effect gating [13], heterointerfaces with LaTiO 3 [14], or LaAlO 3 [15,16], and δ-doping [17], the interplay between subband quantization and superconductivity can be investigated. Here we exploit interlayer coupling in a δ-doped bilayer system to spatially and flexibly control the subbands. By systematically tuning the interlayer coupling by varying the spacer layer thickness, we can examine the effects of the sub-band quantization on superconductivity.The bilayer samples consist of two Nb:STO δ-doped layers, with an undoped STO spacer of thickness d inter , as well as 100 nm thick undoped STO cap and buffer layers. All samples were fabricated using pulsed laser deposition using growth conditions as reported elsewhere [18]. The thickness of each of the two δ-layers was fixed at a constant value of d doped = 5.4 ± 1 nm, as calibrated from the total thickness and the laser pulse count. The interlayer undoped STO thickness d inter was varied in the range 3.7 ≤ d inter ≤ 272 nm. The dopant concentration of the δ-doped layers was 1 at.%. A schematic of the bilayer samples is shown in Fig.

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Two-Dimensional Quantum Oscillations of the Conductance atLaAlO3/SrTiO3Interfaces

Cited by 257 publications

References 27 publications

High Electron Mobility Thin‐Film Transistors Based on Solution‐Processed Semiconducting Metal Oxide Heterojunctions and Quasi‐Superlattices

High Electron Mobility Thin‐Film Transistors Based on Solution‐Processed Semiconducting Metal Oxide Heterojunctions and Quasi‐Superlattices

Insulator-to-Metal Transition at Oxide Interfaces Induced by WO₃ Overlayers

Tunable coupling of two-dimensional superconductors in bilayer SrTiO3heterostructures

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Two-Dimensional Quantum Oscillations of the Conductance atLaAlO3/SrTiO3Interfaces

Cited by 257 publications

References 27 publications

High Electron Mobility Thin‐Film Transistors Based on Solution‐Processed Semiconducting Metal Oxide Heterojunctions and Quasi‐Superlattices

High Electron Mobility Thin‐Film Transistors Based on Solution‐Processed Semiconducting Metal Oxide Heterojunctions and Quasi‐Superlattices

Insulator-to-Metal Transition at Oxide Interfaces Induced by WO3 Overlayers

Tunable coupling of two-dimensional superconductors in bilayer SrTiO3heterostructures

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Insulator-to-Metal Transition at Oxide Interfaces Induced by WO₃ Overlayers