A neck-collapsing-type lifshitz transition induced by orbital symmetry breaking in lightly hole doped t 2g bands

Kazumichi Ikedo; Yuki Wakisaka; Sizuka Hirata; Kou Takubo; Takashi Mizokawa

doi:10.1143/JPSJ.78.063707

A neck-collapsing-type lifshitz transition induced by orbital symmetry breaking in lightly hole doped t _2g bands

Kazumichi Ikedo^*, Yuki Wakisaka, Sizuka Hirata, Kou Takubo, Takashi Mizokawa

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

We report on a new type of orbital symmetry breaking in the CoO ₂ triangular lattice with hole doped t _2g bands. Unrestricted Hartree-Fock calculations on a multi-orbital d-p Hamiltonian show that, in the lightly hole doped t _2g bands, the é _g orbitals are fully occupied with a circular charge distribution, and the doped holes in the a _1g band form a hole pocket sandwiched by two concentric Fermi surfaces with sixfold (and almost continuous) rotational symmetry. This symmetric state has an instability to an anisotropic state with twofold rotational symmetry, where the hole pocket is split into two pieces. This transition is governed by the anisotropic interaction between the a _1g and é _g orbitals.

Original language	English
Article number	063707
Journal	journal of the physical society of japan
Volume	78
Issue number	6
DOIs	https://doi.org/10.1143/JPSJ.78.063707
Publication status	Published - 2009 Jun
Externally published	Yes

Keywords

Band jahn-teller effect
CoO triangular lattice
Lifshitz transition
Orbital degeneracy

ASJC Scopus subject areas

Physics and Astronomy(all)

Access to Document

10.1143/JPSJ.78.063707

Cite this

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title = "A neck-collapsing-type lifshitz transition induced by orbital symmetry breaking in lightly hole doped t 2g bands",

abstract = "We report on a new type of orbital symmetry breaking in the CoO 2 triangular lattice with hole doped t 2g bands. Unrestricted Hartree-Fock calculations on a multi-orbital d-p Hamiltonian show that, in the lightly hole doped t 2g bands, the {\'e} g orbitals are fully occupied with a circular charge distribution, and the doped holes in the a 1g band form a hole pocket sandwiched by two concentric Fermi surfaces with sixfold (and almost continuous) rotational symmetry. This symmetric state has an instability to an anisotropic state with twofold rotational symmetry, where the hole pocket is split into two pieces. This transition is governed by the anisotropic interaction between the a 1g and {\'e} g orbitals.",

keywords = "Band jahn-teller effect, CoO triangular lattice, Lifshitz transition, Orbital degeneracy",

author = "Kazumichi Ikedo and Yuki Wakisaka and Sizuka Hirata and Kou Takubo and Takashi Mizokawa",

year = "2009",

month = jun,

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language = "English",

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journal = "journal of the physical society of japan",

issn = "0031-9015",

publisher = "Physical Society of Japan",

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T1 - A neck-collapsing-type lifshitz transition induced by orbital symmetry breaking in lightly hole doped t 2g bands

AU - Ikedo, Kazumichi

AU - Wakisaka, Yuki

AU - Hirata, Sizuka

AU - Takubo, Kou

AU - Mizokawa, Takashi

PY - 2009/6

Y1 - 2009/6

N2 - We report on a new type of orbital symmetry breaking in the CoO 2 triangular lattice with hole doped t 2g bands. Unrestricted Hartree-Fock calculations on a multi-orbital d-p Hamiltonian show that, in the lightly hole doped t 2g bands, the é g orbitals are fully occupied with a circular charge distribution, and the doped holes in the a 1g band form a hole pocket sandwiched by two concentric Fermi surfaces with sixfold (and almost continuous) rotational symmetry. This symmetric state has an instability to an anisotropic state with twofold rotational symmetry, where the hole pocket is split into two pieces. This transition is governed by the anisotropic interaction between the a 1g and é g orbitals.

AB - We report on a new type of orbital symmetry breaking in the CoO 2 triangular lattice with hole doped t 2g bands. Unrestricted Hartree-Fock calculations on a multi-orbital d-p Hamiltonian show that, in the lightly hole doped t 2g bands, the é g orbitals are fully occupied with a circular charge distribution, and the doped holes in the a 1g band form a hole pocket sandwiched by two concentric Fermi surfaces with sixfold (and almost continuous) rotational symmetry. This symmetric state has an instability to an anisotropic state with twofold rotational symmetry, where the hole pocket is split into two pieces. This transition is governed by the anisotropic interaction between the a 1g and é g orbitals.

KW - Band jahn-teller effect

KW - CoO triangular lattice

KW - Lifshitz transition

KW - Orbital degeneracy

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