NUM / LMU Seminar

Title:
Zero-field phase transitions in gapped quantum magnets

Speaker:
Dr. Alexandra Mannig
Department of Physics, ETH Zürich.


Time:
Monday, November 27th 2017, 14:00

Place:
WWHB/106

Abstract:
Quantum magnets with a spin gap in their excitation spectrum are ideal experimental models for the study of quantum phase transitions and quantum critical points. Research in these systems has focused on field-induced quantum phase transitions. A qualitatively different class of quantum phase transitions can be induced by the application of external pressure or the introduction of chemical disorder in zero-magnetic fields.

In this talk I will present µSR, neutron scattering and thermodynamic studies on magnetic ordering in zero-magnetic fields in selected gapped quantum magnets at low-temperatures and high pressures. I will also compare the results to existing theoretical predictions.

First, the pressure-induced ordering close to a z=1 quantum critical point in the presence of bond disorder in (C4H12N2)Cu2Cl6 (PHCC) will be discussed. Second, it will be demonstrated that it is not possible to induce a quantum phase transition with dynamical critical exponent z=1 by application of hydrostatic pressure in the gapped S=1 quantum paramagnet NiCl2.4SC(NH2)2 (DTN). Finally, the disorder-induced quantum phase transition in bond-disordered DTN will be presented. The transition is qualitatively similar to a z=1 quantum critical point. However, the determined critical scaling of thermodynamic and magnetic properties showed unexpected critical exponents.
Other seminars / events at PSI:

Archive of Events and Seminars at LMU

2017

Date Location Event Details
27.11.2017
14:00
WWHB/106
Zero-field phase transitions in gapped quantum magnets
Dr. Alexandra Mannig - Department of Physics, ETH Zürich

Abstract

18.08.2017
14:00
WBGB/019
Monolithic active pixel sensors for the Mu3e experiment
Prof. Niklaus Berger - Johannes Gutenberg Universität, Germany

Abstract

13.07.2017
14:00
WBGB/019
Complementary response of static spin-stripe order and superconductivity to non-magnetic impurities and pressure in cuprates
Dr. Zurab Guguchia - Department of Physics, Columbia University, USA

Abstract

21.06.2017
14:00
WBGB/019
Exploring non-equiblirum behaviour in frustrated magnetic systems
Dr. Sean Giblin - Cardiff University, United Kingdom

Abstract

26.04.2017
14:00
WBGB/019
Engineering Approach to Instrumentation Development for High-Pressure Research
Prof. Konstantin Kamenev - The University of Edinburgh, United Kingdom

Abstract

2016

Date Location Event Details
07.10.2016
10:15
WBBA/008
Pressure evolution of the magnetic order: muon-spin rotation study of the binary pnictides CrAs, MnP, and FeSe
Dr. Rustem Khasanov - Paul Scherrer Institut, 5232 Villigen PSI, Switzerland

Abstract

07.10.2016
08:30
WBBA/008
Magnetism and Superconductivity in Fe-based Compounds - The Various Ways to Coexist
Dr. Hubertus Luetkens - Paul Scherrer Institut, 5232 Villigen PSI, Switzerland

Abstract

19.09.2016
10:00
WBGB/019
Development of a novel low-energy, high-brightness μ+ beam line
Dr. Andreas Eggenberger - Institute for Particle Physics, ETH, 8093 Zurich, Switzerland

Abstract

23.06.2016
14:00
WBBA/008
Ideal gas of vortices and a filament phase in type-II superconductors
Prof. Vladimir Kozhevnikov - Department of Physics, Tulsa Community College, USA

Abstract

17.06.2016
10:00
WBGB/019
Breaking chains and squeezing ladders: Experimental study of clean and dirty quantum magnets
Mr. Gediminas Simutis - NSM laboratory, ETH Zurich, Switzerland

Abstract

16.06.2016
14:00
WBGB/019
Slow muon study of solar cell materials: Single layers and p-n junctions
Dr. Helena Alberto - Department of Physics, University of Coimbra, Portugal

Abstract

2015

Date Location Event Details
20.10.2015
09:30
WBGB/020
Spin Liquid Ground State in a Vanadium Based S = 1/2 Trimerized Kagome Compound
Dr. Jean-Christophe Orain, Lab. de Physique des Solides, Université Paris-Sud

Abstract

25.09.2015
09:30
WBGB/019
Magnetic nanoparticles - fundamental physics and a novel approach to the problem of cellular uptake
Dr. Tomas Orlando, Università degli Studi di Pavia, Italy

Abstract

10.09.2015
14:00
WHGA/121
ARPES measurements in the presence of electrical current
Mr. Muntaser Naamneh, Technion – Israel Institute of Technology, Israel

Abstract

05.06.2015
14:00
WBGB/019
The topological crystalline insulator (Pb,Sn)Se: From its discovery to controlled surface-state manipulation
Dr. Bastian Wojek, KTH Royal Institute of Technology, Sweden

Abstract

03.03.2015
14:00
WBGB/021
Dynamic Kernel Scheduler (DKS) - a thin software layer between host application and hardware
Mr. Uldis Locans, Paul scherrer Institute

Abstract

2014

Date Location Event Details
27.11.2014
14:00
WHGA/121
Spin-orbital entangled and spin liquid state in the 6H-perovskite compounds Ba3AB2O9 (A=Cu,Ru,Ir;B=Sb,Ti)
Kwang-Yong Choi, Chung-Ang University, Seoul, Korea

Abstract

12.11.2014
10:00
WHGA/121
Microscopic parameters of superconductors from muSR spectra. What can we learn from the intermediate state?
Vladimir Kozhevnikov, Tulsa Community College, USA

Abstract

2012

Date Location Event Details
15.11.2012
10:30
WHGA/121
Microwave absorption study of pinning regimes in iron-pnictide superconductors
Nadezda Panarina, Leibniz Institute for Solid State and Materials Research IFW, Dresden, Germany and Zavoisky Physical-Technical Institute, Kazan, Russian Federation

Abstract