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ID 14995
file
creator
Umeo, K.
Masumori, K.
Sasakawa, T.
Iga, F.
Ohishi, Y.
Adachi, T.
abstract
We report on the electrical resistivity, thermal expansion, and x-ray diffraction measurements of single-crystalline sample of the so-called Kondo semiconductor CeRhAs under pressures up to 3 GPa. This compound undergoes successive structural phase transitions at T1 = 360, T2 = 235, and T3 = 165 K at ambient pressure. On cooling below T1, the crystal structure changes from the hexagonal LiGaGe-type to the orthorhombic epsilon-TiNiSi-type with a 2b×2c superlattice. By applying pressure up to 1.5 GPa, T1 increases with a ratio of 270 K/GPa, whereas both T2 and T3 decrease with –100 K/GPa. The concurrent decrease of both the a parameter and the energy gap along the a axis with increasing pressure contradict the c-f hybridization gap model in which the gap is enlarged by the enhancement of hybridization between the 4f electrons and conduction band. Instead, a sort of charge-density-wave transition at T1 is proposed for the origin of gap formation of this compound. The semiconducting behavior in the resistivity vanishes when the phase with the 2b×2c superlattice decomposes into two orthorhombic phases below 100 K and above 1.5 GPa.
journal title
Physical Review B
volume
Volume 71
start page
064110
date of issued
2005
publisher
American Physical Society
issn
1098-0121
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
Copyright (c) 2006 American Physical Society
relation is version of URL
http://dx.doi.org/10.1103/PhysRevB.71.064110
department
Graduate School of Advanced Sciences of Matter