Infrared absorption study of Ca2- xNaxCuO 2X2 (X=Cl, Br)

Takumi Hasegawa; Norio Ogita; Toshihisa Kondo; Yuji Zenitani; Hirokazu Kawashima; Teruhiko Suzuki; Jun Akimitsu; Masayuki Udagawa

doi:10.1063/1.2354820

Infrared absorption study of Ca_{2- x}Na_xCuO ₂X₂ (X=Cl, Br)

Takumi Hasegawa, Norio Ogita, Toshihisa Kondo, Yuji Zenitani, Hirokazu Kawashima, Teruhiko Suzuki, Jun Akimitsu, Masayuki Udagawa

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

Abstract

IR-active phonon spectra of Ca_{2- x}Na_xCuO ₂X₂ (X=Cl, Br) have been measured by a CsI powder method in the energy region between 250 and 4000 cm^-1 at room temperature. Two absorption peaks with the E_u symmetry have been clearly observed for the undoped crystals of Ca₂CuO₂Cl₂ and Ca₂CuO₂Br₂. However, the observed two peaks disappear for the Na-doped superconducting samples. From the comparison of the highest-energy E_u phonon, which is the Cu-O stretching vibration, the interaction of the Cu-O bond along the CuO₂ plane for the T-structure is stronger by 20 % than that of the T′-structure in the 2-1-4 family. To understand the effect of the apical ions, first-principles calculations of the E_u phonon energy for T- and T′-structure La₂CuO₄ is performed and the preliminary results agree with the experimental tendency.

Original language	English
Title of host publication	LOW TEMPERATURE PHYSICS
Subtitle of host publication	24th International Conference on Low Temperature Physics - LT24
Pages	533-534
Number of pages	2
DOIs	https://doi.org/10.1063/1.2354820
Publication status	Published - Dec 1 2006
Externally published	Yes
Event	LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24 - Orlando, FL, United States Duration: Aug 10 2006 → Oct 17 2006

Publication series

Name	AIP Conference Proceedings
Volume	850
ISSN (Print)	0094-243X
ISSN (Electronic)	1551-7616

Other

Other	LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24
Country/Territory	United States
City	Orlando, FL
Period	8/10/06 → 10/17/06

Keywords

Carrier doping
Infrared absorption
Phonon
Superconductivity

ASJC Scopus subject areas

Physics and Astronomy(all)

Access to Document

10.1063/1.2354820

Cite this

Hasegawa, T, Ogita, N, Kondo, T, Zenitani, Y, Kawashima, H, Suzuki, T, Akimitsu, J & Udagawa, M 2006, Infrared absorption study of Ca_{2- x}Na_xCuO ₂X₂ (X=Cl, Br). in LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24. AIP Conference Proceedings, vol. 850, pp. 533-534, LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24, Orlando, FL, United States, 8/10/06. https://doi.org/10.1063/1.2354820

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abstract = "IR-active phonon spectra of Ca2- xNaxCuO 2X2 (X=Cl, Br) have been measured by a CsI powder method in the energy region between 250 and 4000 cm-1 at room temperature. Two absorption peaks with the Eu symmetry have been clearly observed for the undoped crystals of Ca2CuO2Cl2 and Ca2CuO2Br2. However, the observed two peaks disappear for the Na-doped superconducting samples. From the comparison of the highest-energy Eu phonon, which is the Cu-O stretching vibration, the interaction of the Cu-O bond along the CuO2 plane for the T-structure is stronger by 20 % than that of the T′-structure in the 2-1-4 family. To understand the effect of the apical ions, first-principles calculations of the Eu phonon energy for T- and T′-structure La2CuO4 is performed and the preliminary results agree with the experimental tendency.",

keywords = "Carrier doping, Infrared absorption, Phonon, Superconductivity",

author = "Takumi Hasegawa and Norio Ogita and Toshihisa Kondo and Yuji Zenitani and Hirokazu Kawashima and Teruhiko Suzuki and Jun Akimitsu and Masayuki Udagawa",

year = "2006",

month = dec,

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doi = "10.1063/1.2354820",

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series = "AIP Conference Proceedings",

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T1 - Infrared absorption study of Ca2- xNaxCuO 2X2 (X=Cl, Br)

AU - Hasegawa, Takumi

AU - Ogita, Norio

AU - Kondo, Toshihisa

AU - Zenitani, Yuji

AU - Kawashima, Hirokazu

AU - Suzuki, Teruhiko

AU - Akimitsu, Jun

AU - Udagawa, Masayuki

PY - 2006/12/1

Y1 - 2006/12/1

N2 - IR-active phonon spectra of Ca2- xNaxCuO 2X2 (X=Cl, Br) have been measured by a CsI powder method in the energy region between 250 and 4000 cm-1 at room temperature. Two absorption peaks with the Eu symmetry have been clearly observed for the undoped crystals of Ca2CuO2Cl2 and Ca2CuO2Br2. However, the observed two peaks disappear for the Na-doped superconducting samples. From the comparison of the highest-energy Eu phonon, which is the Cu-O stretching vibration, the interaction of the Cu-O bond along the CuO2 plane for the T-structure is stronger by 20 % than that of the T′-structure in the 2-1-4 family. To understand the effect of the apical ions, first-principles calculations of the Eu phonon energy for T- and T′-structure La2CuO4 is performed and the preliminary results agree with the experimental tendency.

AB - IR-active phonon spectra of Ca2- xNaxCuO 2X2 (X=Cl, Br) have been measured by a CsI powder method in the energy region between 250 and 4000 cm-1 at room temperature. Two absorption peaks with the Eu symmetry have been clearly observed for the undoped crystals of Ca2CuO2Cl2 and Ca2CuO2Br2. However, the observed two peaks disappear for the Na-doped superconducting samples. From the comparison of the highest-energy Eu phonon, which is the Cu-O stretching vibration, the interaction of the Cu-O bond along the CuO2 plane for the T-structure is stronger by 20 % than that of the T′-structure in the 2-1-4 family. To understand the effect of the apical ions, first-principles calculations of the Eu phonon energy for T- and T′-structure La2CuO4 is performed and the preliminary results agree with the experimental tendency.

KW - Carrier doping

KW - Infrared absorption

KW - Phonon

KW - Superconductivity

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