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Condensed Matter Physics Commons

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Full-Text Articles in Condensed Matter Physics

Emergent Phenomena In Quantum Critical Systems, Kun Chen Jul 2018

Emergent Phenomena In Quantum Critical Systems, Kun Chen

Doctoral Dissertations

A quantum critical point (QCP) is a point in the phase diagram of quantum matter where a continuous phase transition takes place at zero temperature. Low-dimensional quantum critical systems are strongly correlated, therefore hosting nontrivial emergent phenomena. In this thesis, we first address two decades-old problems on quantum critical dynamics. We then reveal two novel emergent phenomena of quantum critical impurity problems. In the first part of the thesis, we address the linear response dynamics of the $(2+1)$-dimensional $O(2)$ quantum critical universality class, which can be realized in the ultracold bosonic system near the superfluid (SF) to Mott insulator (MI) …


Novel Physical Properties Of Non-Trivial Magnetic Materials: Cr1/3nbs2, Mnsi And Fe3gete2, Jieyu Yi May 2015

Novel Physical Properties Of Non-Trivial Magnetic Materials: Cr1/3nbs2, Mnsi And Fe3gete2, Jieyu Yi

Doctoral Dissertations

Helimagnets and quasi-two-dimensional layered materials have attracted much recent interest due to their rich physical properties and potential for spintronics applications. In this dissertation, the helimagnets Cr1/3NbS2 [chromium one-third niobium disulfide] and thin-film MnSi [manganese silicide] as well as the layered magnetic material Fe3GeTe2 [iron three germanium ditelluride] were extensively and carefully studied. Cr1/3NbS2 was previously reported to be helimagnet with a transition temperature of approximately 120 K. Cr1/3NbS2 has a layered structure with Cr3+ ions intercalating between NbS­2 sheets, and is easily cleaved. Using in-situ …