Universität zu Köln

Engelmayer, Johannes, Lin, Xiao ORCID: 0000-0002-1773-1761, Koc, Fulya, Grams, Christoph P., Hemberger, Joachim, Behnia, Kamran and Lorenz, Thomas ORCID: 0000-0003-4832-5157 (2019). Ferroelectric order versus metallicity in Sr1-xCaxTiO3-delta (x=0.009). Phys. Rev. B, 100 (19). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

We report on a thermal-expansion study of the ferroelectric phase transition in insulating Sr1-xCaxTiO3 (x = 0.009) and its evolution upon increasing charge-carrier concentration up to n similar or equal to 60 x 10(19) cm(-3). Although electric polarization is screened by mobile charge carriers, we find clear signatures of the ferroelectric phase transition in the thermal-expansion coefficient alpha of the weakly doped metallic samples. Upon increasing n, the transition temperature T-C(n) and the magnitude of the anomalies in alpha rapidly decrease up to a threshold carrier density n* above which broadened anomalies remain present. There is no indication for a sign change of alpha as is expected for a pressure-dependent quantum phase transition with n as the control parameter. Thus, the ferroelectric like transition is either continuously fading away or it transforms to another low-temperature phase above n*, but this change hardly affects the temperature-dependent alpha(T) data.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Engelmayer, Johannes UNSPECIFIED UNSPECIFIED UNSPECIFIED Lin, Xiao UNSPECIFIED orcid.org/0000-0002-1773-1761 UNSPECIFIED Koc, Fulya UNSPECIFIED UNSPECIFIED UNSPECIFIED Grams, Christoph P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hemberger, Joachim UNSPECIFIED UNSPECIFIED UNSPECIFIED Behnia, Kamran UNSPECIFIED UNSPECIFIED UNSPECIFIED Lorenz, Thomas UNSPECIFIED orcid.org/0000-0003-4832-5157 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-127721
DOI:	10.1103/PhysRevB.100.195121
Journal or Publication Title:	Phys. Rev. B
Volume:	100
Number:	19
Date:	2019
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics II
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ANTIFERROELECTRIC PHASE-TRANSITION; SOFT PHONON MODES; X-RAY; RAMAN-SCATTERING; STRONTIUM; SRTIO3; (SR1-XCAX)TIO3; DIFFRACTION; RESONANCE; TRANSPORT Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/12772