### Abstract

A Ti-oxide compound in the pyroxene family NaTiSi_{2}O_{6} containing a one-dimensional Ti-O network exhibits a phase transition at T=210K, for which it has been anticipated that the spin-singlet formation is driven by the orbital ordering. We develop a theory that describes the mechanism of this phase transition. We use the Hartree-Fock approximation to the multiband d-p model and derive the groundstate phase diagram in the parameter space. We also use the perturbation theory in the strong correlation limit up to the fourth order of electron hoppings to derive the effective spin-orbital Hamiltonian. We then apply the density-matrix renormalization group method to the derived Hamiltonian and obtain the groundstate phase diagram. Experimental relevance of our results is discussed.

Original language | English |
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Title of host publication | AIP Conference Proceedings |

Pages | 1083-1084 |

Number of pages | 2 |

Volume | 850 |

DOIs | |

Publication status | Published - 2006 |

Externally published | Yes |

Event | LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24 - Orlando, FL, United States Duration: 2006 Aug 10 → 2006 Oct 17 |

### Other

Other | LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24 |
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Country | United States |

City | Orlando, FL |

Period | 06/8/10 → 06/10/17 |

### Fingerprint

### Keywords

- DMRG
- Hartree-Fock calculation
- NaTiSiO
- Orbital ordering
- Perturbation theory
- Pyroxene
- Spin singlet

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

_{2}O

_{6}. In

*AIP Conference Proceedings*(Vol. 850, pp. 1083-1084) https://doi.org/10.1063/1.2355080

**Orbital-driven spin-singlet formation in NaTiSi _{2}O_{6}.** / Shirakawa, T.; Ohta, Y.; Mizokawa, Takashi.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

_{2}O

_{6}. in

*AIP Conference Proceedings.*vol. 850, pp. 1083-1084, LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24, Orlando, FL, United States, 06/8/10. https://doi.org/10.1063/1.2355080

_{2}O

_{6}. In AIP Conference Proceedings. Vol. 850. 2006. p. 1083-1084 https://doi.org/10.1063/1.2355080

}

TY - GEN

T1 - Orbital-driven spin-singlet formation in NaTiSi2O6

AU - Shirakawa, T.

AU - Ohta, Y.

AU - Mizokawa, Takashi

PY - 2006

Y1 - 2006

N2 - A Ti-oxide compound in the pyroxene family NaTiSi2O6 containing a one-dimensional Ti-O network exhibits a phase transition at T=210K, for which it has been anticipated that the spin-singlet formation is driven by the orbital ordering. We develop a theory that describes the mechanism of this phase transition. We use the Hartree-Fock approximation to the multiband d-p model and derive the groundstate phase diagram in the parameter space. We also use the perturbation theory in the strong correlation limit up to the fourth order of electron hoppings to derive the effective spin-orbital Hamiltonian. We then apply the density-matrix renormalization group method to the derived Hamiltonian and obtain the groundstate phase diagram. Experimental relevance of our results is discussed.

AB - A Ti-oxide compound in the pyroxene family NaTiSi2O6 containing a one-dimensional Ti-O network exhibits a phase transition at T=210K, for which it has been anticipated that the spin-singlet formation is driven by the orbital ordering. We develop a theory that describes the mechanism of this phase transition. We use the Hartree-Fock approximation to the multiband d-p model and derive the groundstate phase diagram in the parameter space. We also use the perturbation theory in the strong correlation limit up to the fourth order of electron hoppings to derive the effective spin-orbital Hamiltonian. We then apply the density-matrix renormalization group method to the derived Hamiltonian and obtain the groundstate phase diagram. Experimental relevance of our results is discussed.

KW - DMRG

KW - Hartree-Fock calculation

KW - NaTiSiO

KW - Orbital ordering

KW - Perturbation theory

KW - Pyroxene

KW - Spin singlet

UR - http://www.scopus.com/inward/record.url?scp=33947604808&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33947604808&partnerID=8YFLogxK

U2 - 10.1063/1.2355080

DO - 10.1063/1.2355080

M3 - Conference contribution

AN - SCOPUS:33947604808

SN - 0735403473

SN - 9780735403475

VL - 850

SP - 1083

EP - 1084

BT - AIP Conference Proceedings

ER -