Single Crystal Growth and Physical Characterization of Strongly Correlated Materials
Lead Research Organisation:
University of Liverpool
Department Name: Physics
Abstract
Many materials studied within condensed matter physics are insensitive to the repulsive Coulombic interactions between electrons; simple metals and semiconductors possess this insensitivity. In such materials the kinetic energy of electrons dominate the electron-electron interaction, this is a consequence of the Pauli exclusion principle and the delocalized nature of the electron states. For these materials the electronic behavior can be theoretically studied with well developed perturbative techniques such as the (k P) expansion, the local density approximation and the Hartree-Fock approximation. In comparison, materials with open d and f electrons shells with electrons occupying narrow orbitals are greatly affected by the repulsive electron-electron interaction. This strong Coulombic repulsion leads to spatial confinement of the electrons within their orbital. This class of material are called strongly correlated materials. In strongly correlated materials, standard perturbative techniques are no longer applicable due to the electron-electron interactions invalidating the independent-electron approach whilst theoretical models for strongly correlated materials, such as dynamical mean field theory (DMFT), are still in their infancy. To further develop these theoretical models it is important that the fermiologies of strongly correlated materials are investigated and understood.
When a material transitions to the strongly correlated phase there is often a remarkable change in physical properties due to the difference in electronic and magnetic order between phases. Examples of the phenomena associated with electronic correlations are metal-insulator transitions, colossal magnetoresistance and superconductivity. These phenomena could lead to technological advancements whereby some small change in a controllable parameter e.g. temperature, pressure or field, can lead to a dramatic change in a physical property, such as a many orders-of-magnitude change in electrical conductivity in a metal-insulator transition. This is a quasiparticle study due to the metastable life times of the correlated electron properties following the phase transition; quasiparticles form an interesting field of study within condensed matter physics which has yet to be fully understood.
This PhD project shall study the single crystal growth and physical characterization of strongly correlated materials in order to investigate the fermiology of this class of material. X-ray diffraction will be used to study the structures and phases of materials produced. Electro- and magneto- transport properties will be studied to investigate the change in properties as samples transition into the strongly correlated regime. The Fermi surfaces will be constructed via the de Haas- van Alphen effect, along with anisotropic magnetoresistance and angular resolved photoemission spectroscopy to further understand the nature of the fermiology of the materials studied. Strongly correlated metal oxides and concentrated ferromagnetic semiconductors are the two classes of strongly correlated material to be studied in detail within this project although expansion into other classes of strongly correlated material is possible as the project progresses.
When a material transitions to the strongly correlated phase there is often a remarkable change in physical properties due to the difference in electronic and magnetic order between phases. Examples of the phenomena associated with electronic correlations are metal-insulator transitions, colossal magnetoresistance and superconductivity. These phenomena could lead to technological advancements whereby some small change in a controllable parameter e.g. temperature, pressure or field, can lead to a dramatic change in a physical property, such as a many orders-of-magnitude change in electrical conductivity in a metal-insulator transition. This is a quasiparticle study due to the metastable life times of the correlated electron properties following the phase transition; quasiparticles form an interesting field of study within condensed matter physics which has yet to be fully understood.
This PhD project shall study the single crystal growth and physical characterization of strongly correlated materials in order to investigate the fermiology of this class of material. X-ray diffraction will be used to study the structures and phases of materials produced. Electro- and magneto- transport properties will be studied to investigate the change in properties as samples transition into the strongly correlated regime. The Fermi surfaces will be constructed via the de Haas- van Alphen effect, along with anisotropic magnetoresistance and angular resolved photoemission spectroscopy to further understand the nature of the fermiology of the materials studied. Strongly correlated metal oxides and concentrated ferromagnetic semiconductors are the two classes of strongly correlated material to be studied in detail within this project although expansion into other classes of strongly correlated material is possible as the project progresses.
People |
ORCID iD |
Jonathan Alaria (Primary Supervisor) | |
Philip Murgatroyd (Student) |
Publications
Gibson QD
(2020)
Modular Design via Multiple Anion Chemistry of the High Mobility van der Waals Semiconductor Bi4O4SeCl2.
in Journal of the American Chemical Society
Markovic I
(2019)
Weyl-like points from band inversions of spin-polarised surface states in NbGeSb.
in Nature communications
Stoner J
(2019)
Chemical Control of Correlated Metals as Transparent Conductors
in Advanced Functional Materials
Studentship Projects
Project Reference | Relationship | Related To | Start | End | Student Name |
---|---|---|---|---|---|
EP/N509693/1 | 30/09/2016 | 29/09/2021 | |||
1797540 | Studentship | EP/N509693/1 | 30/09/2016 | 30/07/2020 | Philip Murgatroyd |
Description | Dave Scanlon |
Organisation | University College London |
Department | Department of Chemistry |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We processed, measured electrical, thermoelectric, and thermal properties of some compounds prepared by the collaborator PhD student. |
Collaborator Contribution | The collaborator performed advanced DFT calculation to predict the thermoelectric properties of compounds studied in this award. |
Impact | Manuscript in preparation |
Start Year | 2016 |
Description | Phil King XRD |
Organisation | University of St Andrews |
Department | School of Physics and Astronomy |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We are assessing the quality and thickness of films grown by MBE. |
Collaborator Contribution | They are providing samples suitable to be measured in the diffractometer purchased with this award. |
Impact | This collaboration is allowing for the optimization of complex inorganic materials growth. |
Start Year | 2017 |