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dc.contributor.author
Galeski, Stanislaw
dc.contributor.supervisor
Zheludev, Andrey
dc.contributor.supervisor
Batlogg, Bertram
dc.contributor.supervisor
Sigrist, Manfred
dc.date.accessioned
2019-01-08T11:25:15Z
dc.date.available
2019-01-08T10:01:42Z
dc.date.available
2019-01-08T11:25:15Z
dc.date.issued
2018
dc.identifier.uri
http://hdl.handle.net/20.500.11850/314212
dc.identifier.doi
10.3929/ethz-b-000314212
dc.description.abstract
Condensed matter physics is perhaps the largest branch of physics currently studied. Al- though progress in this field promises potential applications technological breakthroughs, there is a much more fundamental reason for such interest in this field. Part of the explanation lies in the inherently many-body nature of condensed matter. Properties and laws governing single particles become far more complex when a large number of objects begins to interact with one another. Such aggregates often exhibit new emergent properties that cannot be easily inferred from the basic law governing their constituents. This is the reason underlying the richness of different possible states of condensed matter. The past years were witness of a rapid development in both experimental and theoreti- cal techniques giving us the tools to understand condensed matter at an unprecedented level. However in many sub-fields the experimental and theoretical understanding did not progress in parallel. One such example is the discovery of high temperature superconductivity. Since their discovery in 1986 experimentalists have collected overwhelming amount of data which to a large extent still remains mysterious. At the same time theoretical studies of one dimensional systems reached maturity, with current work often focusing on clarifying fine details of the existing theories. Interestingly until recently these works have been largely unconfirmed experimentally due to the lack of appropriate experimental realizations of the proposed models.This thesis explores problems in both ends of the spectrum. The rst part of this work focuses on exploratory study of two new and relatively poorly understood materials: SmFeAs(O, F) and Na x CoO 2 . In the study of SmFeAs(O, F) a novel multi-band high temperature superconductor a series of thermodynamic and transport measurements was performed to uncover to what extent conductivity and specific heat in this new material can be described using the simple Lowest Landau Level scaling relations. In addition this study was a practice ring for the development and testing of a setup allowing specific heat measurements of nano-gram samples. For Na x CoO 2 the calorimetry setup was used in combination with x-ray diffraction to uncover the relation between different high temperature Na ordering patterns and the low temperature magnetic states they induces. Rapid quenching of the sample, due to the extremely short relaxation times of the calorimeter allowed to establish the two key roles sodium intercalation plays in the formation of the magnetic ground state: supplying the proper electron count and providing an inter-plane anti-ferromagnetic exchange path. The second part of this thesis focuses on both experimental and numerical investigation of the physics of depleted spin ladders. In the first study the emergence of spin islands in the Haldane phase of the spin ladders is studied. Through a combination of magnetic measurements and neutron spectroscopy it is shown that disorder-induced degrees of freedom lead to a specific magnetic response, described in terms of new emergent - spin islands. The structure and dynamics of these objects is studied by high-resolution inelastic neutron scattering both in the limit of diluted and strongly interacting spin islands The study of spin islands is followed by the investigation of the role of spin depletion in the magnetized - Luttinger phase of the ladder. Here a combination of Quantum Monte Carlo simulations and extensive low temperature specific heat measurements is used to uncover whether introduction of non-magnetic impurities to a spin ladder leads to its effective segmentation and emergence of LT scaling. The materials and methods used throughout this work are briefy explained chapter 1. As most of the methods used in this work is extensively covered in a selection of excellent textbooks only the basic information necessary for understanding the subsequent chapters is introduces.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
ETH Zurich
en_US
dc.rights.uri
http://rightsstatements.org/page/InC-NC/1.0/
dc.subject
Quantum magnetism
en_US
dc.subject
Electron correlation
en_US
dc.subject
Superconductivity
en_US
dc.subject
Luttinger liquid
en_US
dc.subject
Superstructures
en_US
dc.title
Phase Transitions and Electron Correlation in: Depleted Spin Ladders, Itinerant Electrons on Triangular Lattices and Unconventional Iron Based Superconductors
en_US
dc.type
Doctoral Thesis
dc.rights.license
In Copyright - Non-Commercial Use Permitted
ethz.size
114 p.
en_US
ethz.code.ddc
DDC - DDC::5 - Science::530 - Physics
ethz.code.ddc
DDC - DDC::5 - Science::530 - Physics
en_US
ethz.identifier.diss
25520
en_US
ethz.publication.place
Zurich
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02010 - Dep. Physik / Dep. of Physics::02505 - Laboratorium für Festkörperphysik / Laboratory for Solid State Physics::03855 - Zheludev, Andrey / Zheludev, Andrey
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02010 - Dep. Physik / Dep. of Physics::02505 - Laboratorium für Festkörperphysik / Laboratory for Solid State Physics::03855 - Zheludev, Andrey / Zheludev, Andrey
en_US
ethz.date.deposited
2019-01-08T10:01:49Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2019-01-08T11:26:53Z
ethz.rosetta.lastUpdated
2021-02-15T03:15:11Z
ethz.rosetta.versionExported
true
ethz.COinS
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