Oxygen vacancies-induced metal-insulator transition in La2/3Sr1/3VO3 thin films: Role of the oxygen substrate-to-film transfer

Hu, Lin; Luo, X.; Zhang, K. J.; Tang, Xianwu; Zu, Lin; Xie, Kun; Chen, L.; Zhu, Xiangrong; Song, Weijie; Dai, Jianming; Sun, Yan

doi:10.1063/1.4896159

Cited by 15 publications

(10 citation statements)

References 25 publications

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“…It is clear that the LSVO thin films show metallic (d R S /d T > 0) and insulating behaviors (d R S /d T < 0) at high and low temperatures, respectively. The LSVO thin films exhibit a metal–insulator transition with a characteristic temperature ( T MIT ) when decreasing temperature, which is consistent with our previous study . The R S (σ) at room temperature is 1123 (742.3), 510.5 (816.3), and 238.9 (872.3) Ω sq −1 (S cm −1 ) for the 12, 24, and 48 nm LSVO thin films, respectively.…”

supporting

confidence: 91%

“…The remarkable elongation of the out‐of‐plane lattice parameter cannot be caused by the small in‐plane compressive strain (0.52%) due to the lattice mismatch between LSVO and LSAT . The origination of the lattice expansion can be ascribed to the presence of oxygen vacancies in the LSVO thin films . The formation of oxygen vacancies will generate two electrons per vacancy site and compensate the hole carriers.…”

mentioning

confidence: 99%

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La_2/3Sr_1/3VO₃ Thin Films: A New p‐Type Transparent Conducting Oxide with Very High Figure of Merit

Wei

Yan

et al. 2018

Adv Elect Materials

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is directly related to its carrier concentration (n) and carrier mobility (μ) by σ = neμ where e is the elemental charge. The carrier mobility is given by / µ τ = * e m with τ being the carrier relaxation time and m* the carrier effective mass. [5] The optical transparency (T opt ) is exponentially proportional to both optical absorption coefficient (α) and film thickness (d), via T opt ∝ e -αd . [6] The T opt of a thin film can be optimized by choosing the material with weak absorption or decreasing the film thickness. Accordingly, the strong optical absorption due to the direct interband transition usually characterizes the optical bandgap.A typical approach to TCOs is starting from wide bandgap oxides (e.g., In 2 O 3 , SnO 2 , and ZnO) and making them conducting by doping, which is successful in developing a series of high-performance n-type TCOs such as Sn-doped In 2 O 3 (ITO), Al-doped ZnO (AZO), and F-doped SnO 2 (FTO). [7][8][9][10] The conduction band minimum (CBM) and valence band maximum (VBM) of these parent oxides are primarily consisted of the unoccupied ns 0 orbital and fully occupied oxygen 2p orbital, respectively. The highly dispersive CBM of ns orbital gives small (high) m* (μ) and excellent n-type conductivity by donor doping. [1,9] However, a straightforward transformation of the n-type TCOs to p-type TCOs via acceptor doping is very difficult. The localized oxygen 2p orbital at the VBM leads to large (low) hole m* (μ), which becomes the fundamental limitation to obtain highly mobile holes at the VBM. Furthermore, it is difficult to introduce hole carriers due to the high formation energy of the native acceptors as well as the self-compensation effect (easily formed native donors annihilate holes). [11,12] Engineering the VBM by alloying the oxygen 2p orbitals with the d or s orbitals of metal cations, i.e., "chemical modulation of the valence band" (CMVB) proposed by Kawazoe et al., has been used to solve this conundrum and promoted the development of a number of p-type TCOs. [13][14][15][16][17][18][19][20][21][22][23] High-throughput material screening has also identified several highly promising p-type TCOs displaying small (high) hole m* (μ). [24][25][26] Despite the improvement of hole mobility, these p-type TCOs still exhibit low σ, several orders of magnitude lower than that of n-type TCOs, primarily due to the doping bottleneck in increasing the hole concentration by intrinsic defects (cation vacancies or interstitial oxygen) and/or the solubility limit of the acceptors. Transparent conducting oxides (TCOs) are a unique series of materials combining electrical conductivity with optical transparency. Most of the commercially available TCOs are of the n-type. The performance of p-type TCOs, however, is far behind their n-type TCO counterparts primarily due to the doping bottleneck and low hole mobility. Herein, a Mott-Hubbard insulator of LaVO 3 is proposed as the starting point for exploring p-type TCOs. Substitution of La 3+ by Sr 2+ can introduce high hole carrier concentration at th...

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confidence: 91%

mentioning

confidence: 99%

La_2/3Sr_1/3VO₃ Thin Films: A New p‐Type Transparent Conducting Oxide with Very High Figure of Merit

Wei

Yan

et al. 2018

Adv Elect Materials

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“…In this regard, oxygen vacancies behave in many 3d-oxoperovskites as mobile, e-donor defects, able to induce profound changes in the structural, electronic and magnetic properties of the material. [4][5][6] Therefore, the possibility to control at will not only the creation of these vacancies, but also their distribution and movement inside the material using different external stimuli, is key for the design of ionic-based devices. 7 Strontium titanate, SrTiO 3 (STO) is a paradigmatic example in this regard.…”

Section: Introductionmentioning

confidence: 99%

Tuning Oxygen Vacancy Diffusion through Strain in SrTiO₃ Thin Films

Iglesias

Gómez

Gich

et al. 2018

ACS Appl. Mater. Interfaces

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Understanding the diffusion of oxygen vacancies in oxides under different external stimuli is crucial for the design of ion-based electronic devices, improve catalytic performance, etc. In this manuscript, using an external electric field produced by an AFM tip, we obtain the room-temperature diffusion coefficient of oxygen-vacancies in thin-films of SrTiO 3 under compressive/tensile epitaxial strain. Tensile strain produces a substantial increase of the diffusion coefficient, facilitating the mobility of vacancies through the film. Additionally, the effect of tip bias, pulse time, and temperature on the local concentration of vacancies is investigated. These are important parameters of control in the production and stabilization of non-volatile states in ion-based memresistive devices. Our findings show the key role played by strain for the control of oxygen vacancy migration in thin-film oxides.1

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“…A multilayer with 20 layers of nominally 10 unit cells thick LaVO 3 and 7 unit cells thick La 0.75 Sr 0.25 VO 3 was made under the same growth conditions as the bare films . LaGaO 3 substrates (pseudocubic a pc = 3.88 Å) are a good choice because of the very good lattice match with both LaVO 3 ( a pc = 3.925 Å) and La 0.75 Sr 0.25 VO 3 ( a pc = 3.896 Å) at room temperature (RT) . Moreover, LaGaO 3 is suitable for Raman scattering spectroscopy of LaVO 3 films as it has no Raman active modes and has low background in the vicinity of the main Raman bands of LaVO 3 .…”

Section: Experimental Methodsmentioning

confidence: 99%

Structure and orbital ordering of ultrathin LaVO₃probed by atomic resolution electron microscopy and Raman spectroscopy

Lindfors‐Vrejoiu

Jin

Himcinschi

et al. 2017

Phys. Status Solidi RRL

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Orbital ordering has been less investigated in epitaxial thin films, due to the difficulty to evidence directly the occurrence of this phenomenon in thin film samples. Atomic resolution electron microscopy enabled us to observe the structural details of the ultrathin LaVO3 films. The transition to orbital ordering of epitaxial layers as thin as ≈4 nm was probed by temperature‐dependent Raman scattering spectroscopy of multilayer samples. From the occurrence and temperature dependence of the 700 cm–1 Raman active mode it can be inferred that the structural phase transition associated with orbital ordering takes place in ultrathin LaVO3 films at about 130 K.

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Oxygen vacancies-induced metal-insulator transition in La2/3Sr1/3VO3 thin films: Role of the oxygen substrate-to-film transfer

Cited by 15 publications

References 25 publications

La_2/3Sr_1/3VO₃ Thin Films: A New p‐Type Transparent Conducting Oxide with Very High Figure of Merit

La_2/3Sr_1/3VO₃ Thin Films: A New p‐Type Transparent Conducting Oxide with Very High Figure of Merit

Tuning Oxygen Vacancy Diffusion through Strain in SrTiO₃ Thin Films

Structure and orbital ordering of ultrathin LaVO₃probed by atomic resolution electron microscopy and Raman spectroscopy

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Oxygen vacancies-induced metal-insulator transition in La2/3Sr1/3VO3 thin films: Role of the oxygen substrate-to-film transfer

Cited by 15 publications

References 25 publications

La2/3Sr1/3VO3 Thin Films: A New p‐Type Transparent Conducting Oxide with Very High Figure of Merit

La2/3Sr1/3VO3 Thin Films: A New p‐Type Transparent Conducting Oxide with Very High Figure of Merit

Tuning Oxygen Vacancy Diffusion through Strain in SrTiO3 Thin Films

Structure and orbital ordering of ultrathin LaVO3probed by atomic resolution electron microscopy and Raman spectroscopy

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La_2/3Sr_1/3VO₃ Thin Films: A New p‐Type Transparent Conducting Oxide with Very High Figure of Merit

La_2/3Sr_1/3VO₃ Thin Films: A New p‐Type Transparent Conducting Oxide with Very High Figure of Merit

Tuning Oxygen Vacancy Diffusion through Strain in SrTiO₃ Thin Films

Structure and orbital ordering of ultrathin LaVO₃probed by atomic resolution electron microscopy and Raman spectroscopy