St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  • Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Fluctuation-driven phase reconstruction at itinerant ferromagnetic quantum critical points

Thumbnail
View/Open
UnaKarahasanovicPhDThesis.pdf (3.715Mb)
Date
30/11/2012
Author
Karahasanovic, Una
Supervisor
Green, Andrew George
Funder
ORS
Engineering and Physical Sciences Research Council (EPSRC)
Keywords
Condensed matter theory
Quantum criticality
Metadata
Show full item record
Altmetrics Handle Statistics
Abstract
The formation of new phases close to itinerant electron quantum critical points has been observed experimentally in many compounds. We present a unified analytical model that explains the emergence of new types of phases around itinerant ferromagnetic quantum critical points. The central idea of our analysis is that certain deformations of the Fermi surface enhance the phase-space available for low-energy quantum fluctuations and so self-consistently lower the free energy. Using this quantum order-by-disorder mechanism, we find instabilities towards the formation of a spiral ferromagnet and spin-nematic phase close to an itinerant ferromagnetic quantum critical point. Further, we employ the quantum order-by-disorder mechanism to describe the partially ordered phase of MnSi. Using the simplest model of a Stoner-like helimagnetic transition, we show that quantum fluctuations naturally lead to the formation of an unusual phase near to the putative quantum critical point that shares many of the observed features of the partially ordered phase in MnSi. In particular, we predict an angular dependence of neutron scattering that is in good agreement with neutron-scattering data.
Type
Thesis, PhD Doctor of Philosophy
Collections
  • Physics & Astronomy Theses
URI
http://hdl.handle.net/10023/3188

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter