Carrier tuning the metal-insulator transition of epitaxial La0.67Sr0.33MnO3 thin film on Nb doped SrTiO3 substrate

J M Zhan,H Ma,H Liu,G L Yuan,J Q Shen,S L Wang,S L Tao,M J Pan,Z J Zhang,P G Li

doi:10.1063/1.4945694

J M Zhan, H Ma + Show 8 more

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https://doi.org/10.1063/1.4945694

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Abstract

La0.67Sr0.33MnO3 (LSMO) thin films were deposited on (001)SrTiO3(STO) and n-type doped Nb:SrTiO3(NSTO) single crystal substrates respectively. The metal to insulator transition temperature(TMI) of LSMO film on NSTO is lower than that on STO, and the TMI of LSMO can be tuned by changing the applied current in the LSMO/NSTO p-n junction. Such behaviors were considered to be related to the carrier concentration redistribution in LSMO film caused by the change of depletion layer thickness in p-n junction which depends greatly on the applied electric field. The phenomenon could be used to configure artificial devices and exploring the underlying physics.

Highlights

La0.67Sr0.33MnO3 (LSMO) thin films were deposited on (001)SrTiO3(STO) and n-type doped Nb:SrTiO3(NSTO) single crystal substrates respectively
The metal to insulator transition temperature(TMI) of LSMO film on NSTO is lower than that on STO, and the TMI of LSMO can be tuned by changing the applied current in the LSMO/NSTO p-n junction. Such behaviors were considered to be related to the carrier concentration redistribution in LSMO film caused by the change of depletion layer thickness in p-n junction which depends greatly on the applied electric field
We found that the metal-insulator transition temperature shifted to higher temperature direction, and the resistance decreased with the increase of the current, the behavior is similar to positive currents, such phenomenon could be explained using La1-xSrxMnO3 phase diagram, in which we can see that the highest TMI of La1-xSrxMnO3 is 0.33 Sr content,[19] meaning that the TMI will shift to lower temperature regardless the carrier concentration increase or decrease