Inelastic Light Scattering Studies of Quantum Phase Transitions in Copper Titanium Diselenium and Multiferroic Terbium Manganese Trioxygen

The second focus of this dissertation is the study of quantum phase transitions in TiSe2 as a function of temperature and Cu-intercalation, and the comparison of the effects of intercalation and pressure on the charge-density-wave (CDW) order in this system. All these parameters---temperature, pressure and Cu-intercalation---suppress the CDW state in TiSe2. Our Raman measurements on CuxTiSe2 show that the x-dependent mode softening exhibits identical scaling behavior to thermal mode softening in undoped TiSe2, suggesting that, like thermal mode softening, the x-dependent mode softening is also associated with a critical point. The softening and significant linewidth broadening of the observed CDW amplitude modes indicate strong fluctuations of the CDW. Even more interesting is the emergence of a superconducting (SC) phase---in CuxTiSe2 and pressure-tuned TiSe 2---indicating a likely coexistence of fluctuating CDW and SC phases near the quantum phase boundary.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Barath, Harini

Contributors dc:contributor

• Abbamonte, Peter M.

• Physics, Condensed Matter

Language dc:language

eng

Identifier

(MiAaPQ)AAI3430925

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/80630