### Abstract

Transport and magnetic properties of R_{1-x}Ca_{x}TiO_{3+y/2} have been systematically investigated varying the one-electron bandwidth (W) and the band filling (n=1 - δ), which can be controlled by the R-dependent lattice distortion and by the Ca content x and/or oxygen offstoichiometry y (δ=x + y), respectively. The end compound RTiO_{3} is a 3d^{1} Mott-Hubbard insulator and its charge-gap magnitude increases with decreasing ionic radius of R, i.e., an increase of electron correlation (U/W) in proportion with (U/W)-(U/W)_{c}, where (U/W)_{c} is the critical value for the (hypothetical) n=1 Mott transition. Such a Mott insulator is transformed to a correlated metal by substitution of R with Ca (hole doping), and the nominal hole concentration required for the insulator-metal transition (δ_{c}) increases in proportion with (U/W)-(U/W)_{c}. Concerning magnetism, RTiO_{3} with R=La, Pr, Nd, and Sm, shows the antiferromagnetic ordering and its Néel temperature (T_{N}) decreases with smaller R. T_{N} also decreases with Ca doping, but remains finite up to the metal-insulator phase boundary. On the basis of these results, electronic phase diagrams are derived for a series of titanates as an electron-correlated system with changes of two parameters, i.e., the strength of electron correlation and band filling. Possible origins of the insulating state with finite hole doping are also discussed in terms of the kinetic energy of doped carriers in the Mott-Hubbard insulator.

Original language | English |
---|---|

Pages (from-to) | 10145-10153 |

Number of pages | 9 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 56 |

Issue number | 16 |

Publication status | Published - 1997 Oct 15 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Condensed Matter Physics

### Cite this

_{1-x}Ca

_{x}TiO

_{3+y/2}.

*Physical Review B - Condensed Matter and Materials Physics*,

*56*(16), 10145-10153.

**Transport and magnetic properties of a Mott-Hubbard system whose bandwidth and band filling are both controllable : R _{1-x}Ca_{x}TiO_{3+y/2}.** / Katsufuji, Takuro; Taguchi, Y.; Tokura, Y.

Research output: Contribution to journal › Article

_{1-x}Ca

_{x}TiO

_{3+y/2}',

*Physical Review B - Condensed Matter and Materials Physics*, vol. 56, no. 16, pp. 10145-10153.

_{1-x}Ca

_{x}TiO

_{3+y/2}. Physical Review B - Condensed Matter and Materials Physics. 1997 Oct 15;56(16):10145-10153.

}

TY - JOUR

T1 - Transport and magnetic properties of a Mott-Hubbard system whose bandwidth and band filling are both controllable

T2 - R1-xCaxTiO3+y/2

AU - Katsufuji, Takuro

AU - Taguchi, Y.

AU - Tokura, Y.

PY - 1997/10/15

Y1 - 1997/10/15

N2 - Transport and magnetic properties of R1-xCaxTiO3+y/2 have been systematically investigated varying the one-electron bandwidth (W) and the band filling (n=1 - δ), which can be controlled by the R-dependent lattice distortion and by the Ca content x and/or oxygen offstoichiometry y (δ=x + y), respectively. The end compound RTiO3 is a 3d1 Mott-Hubbard insulator and its charge-gap magnitude increases with decreasing ionic radius of R, i.e., an increase of electron correlation (U/W) in proportion with (U/W)-(U/W)c, where (U/W)c is the critical value for the (hypothetical) n=1 Mott transition. Such a Mott insulator is transformed to a correlated metal by substitution of R with Ca (hole doping), and the nominal hole concentration required for the insulator-metal transition (δc) increases in proportion with (U/W)-(U/W)c. Concerning magnetism, RTiO3 with R=La, Pr, Nd, and Sm, shows the antiferromagnetic ordering and its Néel temperature (TN) decreases with smaller R. TN also decreases with Ca doping, but remains finite up to the metal-insulator phase boundary. On the basis of these results, electronic phase diagrams are derived for a series of titanates as an electron-correlated system with changes of two parameters, i.e., the strength of electron correlation and band filling. Possible origins of the insulating state with finite hole doping are also discussed in terms of the kinetic energy of doped carriers in the Mott-Hubbard insulator.

AB - Transport and magnetic properties of R1-xCaxTiO3+y/2 have been systematically investigated varying the one-electron bandwidth (W) and the band filling (n=1 - δ), which can be controlled by the R-dependent lattice distortion and by the Ca content x and/or oxygen offstoichiometry y (δ=x + y), respectively. The end compound RTiO3 is a 3d1 Mott-Hubbard insulator and its charge-gap magnitude increases with decreasing ionic radius of R, i.e., an increase of electron correlation (U/W) in proportion with (U/W)-(U/W)c, where (U/W)c is the critical value for the (hypothetical) n=1 Mott transition. Such a Mott insulator is transformed to a correlated metal by substitution of R with Ca (hole doping), and the nominal hole concentration required for the insulator-metal transition (δc) increases in proportion with (U/W)-(U/W)c. Concerning magnetism, RTiO3 with R=La, Pr, Nd, and Sm, shows the antiferromagnetic ordering and its Néel temperature (TN) decreases with smaller R. TN also decreases with Ca doping, but remains finite up to the metal-insulator phase boundary. On the basis of these results, electronic phase diagrams are derived for a series of titanates as an electron-correlated system with changes of two parameters, i.e., the strength of electron correlation and band filling. Possible origins of the insulating state with finite hole doping are also discussed in terms of the kinetic energy of doped carriers in the Mott-Hubbard insulator.

UR - http://www.scopus.com/inward/record.url?scp=0001200066&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0001200066&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0001200066

VL - 56

SP - 10145

EP - 10153

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 0163-1829

IS - 16

ER -