Limit of the electrostatic doping in two-dimensional electron gases of LaXO3(X = Al, Ti)/SrTiO3

Biscaras, Johan; Hurand, S.; Feuillet-Palma, C.; Rastogi, Ankur; Budhani, R. C.; Reyren, Nicolas; Lesne, Edouard; Lesueur, J.; Bergeal, N.

doi:10.1038/srep06788

Cited by 100 publications

(134 citation statements)

References 38 publications

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“…As is common for LAO/STO samples, we find that electrostatic gating irreversibly changes the oxide 2DES 25 and the initial measurements [Figs. 2(b) and 2(c)] were performed after cooldown before applying a gate voltage.…”

supporting

confidence: 54%

Nanoscale patterning of electronic devices at the amorphous LaAlO3/SrTiO3 oxide interface using an electron sensitive polymer mask

Bjørlig

Soosten

Erlandsen

et al. 2018

Applied Physics Letters

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A simple approach is presented for designing complex oxide mesoscopic electronic devices based on the conducting interfaces of room temperature grown LaAlO3/SrTiO3 heterostructures. The technique is based entirely on methods known from conventional semiconductor processing technology, and we demonstrate a lateral resolution of ∼100 nm. We study the low temperature transport properties of nanoscale wires and demonstrate the feasibility of the technique for defining in-plane gates allowing local control of the electrostatic environment in mesoscopic devices.

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supporting

confidence: 54%

Nanoscale patterning of electronic devices at the amorphous LaAlO3/SrTiO3 oxide interface using an electron sensitive polymer mask

Bjørlig

Soosten

Erlandsen

et al. 2018

Applied Physics Letters

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“…Based on the relevant length scale of the phenomenon, we suggest that the trapping sites might be linked to crystal imperfections with similar length scales, such as dislocations and twin boundaries. Interestingly, a recent report shows accelerated recovery of conductivity (after its suppression with gating) in LaTiO 3 /SrTiO 3 system at temperatures close to 70 and 160 K [22], raising the possibility that the relevance of the reported phenomenon exceeds the LAO/STO interface. The samples were grown by pulsed laser deposition in an oxygen atmosphere of 7 × 10 −5 mbar on TiO 2 termi- nated (001) STO surfaces at 770 • C. The LAO thickness is 4 unit cells.…”

mentioning

confidence: 88%

Thermally activated recovery of electrical conductivity inLaAlO3/SrTiO3

2013

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Patterned structures of LaAlO3/SrTiO3 that exhibit a decrease in their electrical conductivity below 30 K, recover their higher conductivity upon warming in a thermally activated process. Two dominant energy barriers E b are identified: E b1 = 0.224 ± 0.003 eV related to conductivity recovery near 70 K and E b2 = 0.44 ± 0.015 eV related to conductivity recovery near 160 K. We discuss possible linkage to structural defects such as dislocations and twin boundaries. PACS numbers:An attractive feature of the interface between the insulating oxides SrTiO 3 and LaAlO 3 (LAO/STO) [1,2] is the ability to tune its transport properties by gate voltage [3][4][5][6][7][8][9][10]. However, it appears that there are other mechanisms that yield effectively the same effect without gating, including similar correlations between sheet resistance, carrier density and mobility. In a recent report [11], we showed that LAO/STO patterns with current path width smaller than 10 microns may exhibit below 30 K a significant decrease in their electrical conductivity, in connection with driving a sufficiently large current through the sample and/or applying an in-plane magnetic field. The initial high conductivity is recoverable upon applying a warming cycle.Concomitantly with the field-and current-induced decrease in conductivity, the sheet carrier density (n s ) and mobility decrease, magnetotransport features linked to magnetism [12][13][14] are suppressed, and the nonuniformity of the sample increases. Namely, without applying a gate voltage, there are mechanisms that decrease conductivity. Furthermore, the mechanism also increases the nonuniformity of the conductivity, a feature that was directly observed with scanning probe microscopy [15,16].Here, we explore in detail the time and temperature dependence of the conductivity recovery as the sample is warmed up and show that it is well described by a thermally activated process. We extract two energy barriers: E b1 = 0.224 ± 0.003 eV for the conductivity recovery near 70 K and E b2 = 0.44 ± 0.015 eV for the conductivity recovery near 160 K. The conductivity exhibits a noticeable time dependence also above room temperature; however, it can not be correlated with a single thermally-activated process.The results not only provide an explanation for a puzzling behavior reported previously [17,18], they also provide quantitative details on what appears to be a lowtemperature charge trapping mechanism that reduces the carrier density and increases nonuniformity. Thus, they provide new insights regarding two of the main issues concerning the transport properties of the LAO/STO interface: the existence and nature of localized charge carriers [19][20][21], and the origins of interface nonuniformity [12,15,16]. The identified energy scales and length scales are instrumental in identifying the trapping sites which would enable better understanding and control of the transport properties of the LAO/STO interface. Based on the relevant length scale of the phenomenon, we suggest that the trapping site...

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“…[39][40][41]. When the temperature is lower than 10 K, the discrepancy between n total and n 0T saturates.…”

mentioning

confidence: 95%

Dual-Gate Modulation of Carrier Density and Disorder in an Oxide Two-Dimensional Electron System

et al. 2016

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Limit of the electrostatic doping in two-dimensional electron gases of LaXO3(X = Al, Ti)/SrTiO3

Cited by 100 publications

References 38 publications

Nanoscale patterning of electronic devices at the amorphous LaAlO3/SrTiO3 oxide interface using an electron sensitive polymer mask

Nanoscale patterning of electronic devices at the amorphous LaAlO3/SrTiO3 oxide interface using an electron sensitive polymer mask

Thermally activated recovery of electrical conductivity inLaAlO3/SrTiO3

Dual-Gate Modulation of Carrier Density and Disorder in an Oxide Two-Dimensional Electron System

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