[Neutron] Four PhD positions in experimental studies of complex solid state phenomena at Helmholtz Centre Berlin

[Marie Haltod]

PhD positions in experimental studies of complex solid state phenomena
at the Helmholtz Centre Berlin for Materials and Energy

The Helmholtz Centre Berlin for Materials and Energy (http://www.helmholtz-berlin.de/) is a German National Laboratory
and a member of the Hermann von Helmholtz Association of National Research Centres. It hosts the Berlin Neutron
scattering centre and the Berlin Synchrotron Radiation Source BESSY, which are outstanding user facilities open to
scientist from all over the world. The Magnetism Division undertakes world leading research in quantum magnetism,
superconductivity and novel materials. It also offers a state-of-the-art materials synthesis program as well as the full
range of standard sample characterization facilities including x-ray Laue and powder diffraction, SQUID, transport and
thermal measurements.

In the framework of the newly established Helmholtz Virtual Institute ‘New states of matter and their excitations’, a
collaborative network of leading scientist throughout Germany and abroad, we invite applications for four PhD positions.

The topics of the projects are as follows:

1. Controlling topological insulators (Ref. No. M2013/2)

The candidate shall carry out experiments with high-resolution angle-resolved photoemission down to 1 Kelvin as well as
spin-resolved photoemission and low-temperature STM to study the states at the surfaces of topological insulators. In
particular, the influence of disorder, ferromagnetism, and electron correlation shall be investigated. His/her activity
will be supported by in-house collaborating groups using photoelectron microscopy and high-field x-ray magnetic circular
dichroism as well as collaborations within the Virtual Institute on sample growth, nanostructuring and transport.

2. Thermal effects in strongly correlated magnets (Ref. No. M2013/3)

The aim of this project is to investigate quantum magnets using primarily the experimental technique of neutron
scattering along with materials synthesis and characterization. There will be particular focus on developing neutron
scattering methods to explore the magnetic excitations to high precision e.g. neutron spin-echo and time-of-flight
techniques. Careful studies as a function of temperature or magnetic field will be used to control the excitations and
will provide additional insight into the exotic ground states and unusual quasi-particles responsible for the properties
of these materials e.g. hard-core Bosons and Majorana Fermions. Deeper understanding of these phenomena will also be
gained by performing computer simulations and by collaboration with theorists.

3. Non equilibrium behavior (Ref. No. M2013/4)

The aim of this project is to develop out-of-equilibrium methods to investigate topological systems. The focus of
development will be on diffuse and small-angle neutron scattering and transport techniques to measure the time
development of perturbed systems. As an ideal subject for this, spin ice will be explored as its relaxation to
equilibrium can be controlled over many decades of time scale. Spin ice is also an exceptionally transparent and very
rare example of fractionalization and topological order.

4. Quantum spin ice (Ref. No. M2013/5)

The spin ice materials Dy2Ti2O7 and Ho2Ti2O7 are Ising spin systems exhibiting classical topological order. The question
that immediately follows is: what happens in a system with quantum tunneling between the classical ground states? Such
materials are collectively known as "quantum spin ice" and the aim of this project is to theoretically investigate their
behavior using Quantum Monte-Carlo simulations and to experimentally realize and study examples of these using
time-of-flight neutron scattering.

The applicants should have or be close to finishing a masters/diploma degree in physics and should have taken courses in
condensed matter physics.

For informal inquiries, please contact:

For Ref. No. M2013/2: apl. Prof. Dr. Oliver Rader (email: rader at helmholtz-berlin.de, phone +49-(0)30-8062-12950)
For Ref. No. M2013/3: Prof. Bella Lake (email: bella.lake at helmholtz-berlin.de, phone +49-(0)30-8062-42058)
For Ref. No. M2013/4 and Ref. No. M2013/5: Prof. Alan Tennant (tennant at helmholtz-berlin.de, phone +49-(0)30-8062-42741)

Applicants should send a letter of application, a detailed CV and the contact details of at least two academic referees
to the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Abt. Personal und Soziales, Hahn-Meitner-Platz 1,
D-14109 Berlin, Germany, (Email: personalabteilung at helmholtz-berlin.de) quoting the reference no of the position you
apply for.

Closing date: 1 March 2013. As HZB endeavors to increase the amount of women working in the scientific field, women are
especially encouraged to apply. Handicapped applicants will be given preference to others of equal qualification.



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Marie Haltod
Sekretariat
Institut für komplexe magnetische Materialien
Institute for Complex Magnetic Materials

phone    +49-30-8062-42689
fax      +49-30-8062-43689
email    haltod at helmholtz-berlin.de

________________________________

Helmholtz-Zentrum Berlin für Materialien und Energie GmbH

Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V.

Aufsichtsrat: Vorsitzender Prof. Dr. Dr. h.c. mult. Joachim Treusch, stv. Vorsitzende Dr. Beatrix Vierkorn-Rudolph
Geschäftsführung: Prof. Dr. Anke Rita Kaysser-Pyzalla, Thomas Frederking

Sitz Berlin, AG Charlottenburg, 89 HRB 5583

Postadresse:
Hahn-Meitner-Platz 1
D-14109 Berlin

http://www.helmholtz-berlin.de