902 citations · 1.5k across the 24 of their papers we have counts for
24 papers
Nonlinear collective dynamics and microwave comb generation in a diamond maser
Christoph W. Zollitsch, Jonas N. Bach, Christopher W. M. Kay +1
Optically pumped room temperature masers are a promising platform for driven dissipative spin photon physics beyond steady state emission. Here we observe a sequence of dynamical t…
Spin-glass states generated in a van der Waals magnet by alkali-ion intercalation
S. Khan, E. S. Y. Aw, L. A. V. Nagle-Cocco +16
Tuning magnetic properties in layered van der Waals (vdW) materials has captured a significant attention due to the efficient control of ground-states by heterostructuring and exte…
Maser Threshold Characterization by Resonator Q-Factor Tuning
Christoph W. Zollitsch, Stefan Ruloff, Yan Fett +4
Whereas the laser is nowadays an ubiquitous technology, applications for its microwave analogue, the maser, remain highly specialized, despite the excellent low-noise microwave amp…
Spin Dynamics in van der Waals Magnetic Systems
Chunli Tang, Laith Alahmed, Muntasir Mahdi +11
The discovery of atomic monolayer magnetic materials has stimulated intense research activities in the two-dimensional (2D) van der Waals (vdW) materials community. The field is gr…
Coherent spin dynamics of rare-earth doped crystals in the high-cooperativity regime
Joseph Alexander, Gavin Dold, Oscar W. Kennedy +9
Rare-earth doped crystals have long coherence times and the potential to provide quantum interfaces between microwave and optical photons. Such applications benefit from a high coo…
Probing spin dynamics of ultra-thin van der Waals magnets via photon-magnon coupling
Christoph W. Zollitsch, Safe Khan, Vu Thanh Trung Nam +9
Layered van der Waals (vdW) magnets can maintain a magnetic order even down to the single-layer regime and hold promise for integrated spintronic devices. While the magnetic ground…
Nonlinear magnon polaritons
Oscar Lee, Kei Yamamoto, Maki Umeda +6
We experimentally and theoretically demonstrate that nonlinear spin-wave interactions suppress the hybrid magnon-photon quasiparticle or "magnon polariton" in microwave spectra of…
Reducing strain in heterogeneous quantum devices using atomic layer deposition
Oscar W. Kennedy, James O'Sullivan, Christoph W. Zollitsch +3
We investigated the use of dielectric layers produced by atomic layer deposition (ALD) as an approach to strain mitigation in composite silicon/superconductor devices operating at…
Spin coherence of near-surface ionised Te donors in silicon
Mantas Šimėnas, James O'Sullivan, Oscar W. Kennedy +8
Impurity spins in crystal matrices are promising components in quantum technologies, particularly if they can maintain their spin properties when close to surfaces and material int…
Random-access quantum memory using chirped pulse phase encoding
James O'Sullivan, Oscar W. Kennedy, Kamanasish Debnath +9
As in conventional computing, key attributes of quantum memories are high storage density and, crucially, random access, or the ability to read from or write to an arbitrarily chos…
Quantum engineering with hybrid magnonics systems and materials
D. D. Awschalom, C. H. R. Du, R. He +19
Quantum technology has made tremendous strides over the past two decades with remarkable advances in materials engineering, circuit design and dynamic operation. In particular, the…
Parity-controlled spin-wave excitations in synthetic antiferromagnets
A. Sud, Y. Koike, S. Iihama +3
We report in this study the current-induced-torque excitation of acoustic and optical modes in Ta/NiFe/Ru/NiFe/Ta synthetic antiferromagnet stacks grown on SiO2/Si substrates. The…
Spin resonance linewidths of bismuth donors in silicon coupled to planar microresonators
James O'Sullivan, Oscar W. Kennedy, Christoph W. Zollitsch +5
Ensembles of bismuth donor spins in silicon are promising storage elements for microwave quantum memories due to their long coherence times which exceed seconds. Operating an effic…
Tunable magnon-magnon coupling in synthetic antiferromagnets
A. Sud, C. W. Zollitsch, A. Kamimaki +5
In this work, we study magnon-magnon coupling in synthetic antiferromagnets (SyAFs) using microwave spectroscopy at room temperature. Two distinct spin-wave modes are clearly obser…
Tuning high-Q superconducting resonators by magnetic field reorientation
Christoph W. Zollitsch, James O'Sullivan, Oscar W. Kennedy +2
Superconducting resonators interfaced with paramagnetic spin ensembles are used to increase the sensitivity of electron spin resonance experiments and are key elements of microwave…
A spin dynamics study in layered van der Waals single crystal, CrGeTe
S. Khan, C. W. Zollitsch, D. M. Arroo +6
We study the magnetisation dynamics of a bulk single crystal CrGeTe (CGT), by means of broadband ferromagnetic resonance (FMR), for temperatures from 60 K down to 2 K.…
High-cooperativity coupling of a rare-earth spin ensemble to a superconducting resonator using yttrium orthosilicate as a substrate
Gavin Dold, Christoph W. Zollitsch, James O'Sullivan +6
Yttrium orthosilicate (YSiO, or YSO) has proved to be a convenient host for rare-earth ions used in demonstrations of microwave quantum memories and optical memories with m…
Quantitative modeling of superconducting planar resonators with improved field homogeneity for electron spin resonance
Stefan Weichselbaumer, Petio Natzkin, Christoph W. Zollitsch +3
We present three designs for planar superconducting microwave resonators for electron spin resonance (ESR) experiments. We implement finite element simulations to calculate the res…
Echo trains in pulsed electron spin resonance of a strongly coupled spin ensemble
Stefan Weichselbaumer, Matthias Zens, Christoph W. Zollitsch +4
We report on a novel dynamical phenomenon in electron spin resonance experiments of phosphorus donors. When strongly coupling the paramagnetic ensemble to a superconducting lumped…
Dissipative discrete time crystals
James O'Sullivan, Oliver Lunt, Christoph W. Zollitsch +3
Periodically driven quantum systems host a range of non-equilibrium phenomena which are unrealizable at equilibrium. Discrete time-translational symmetry in a periodically driven m…
Loss mechanisms in superconducting thin film microwave resonators
Jan Goetz, Frank Deppe, Max Haeberlein +10
We present a systematic analysis of the internal losses of superconducting coplanar waveguide microwave resonators based on niobium thin films on silicon substrates. In particular,…
Tunable coupling of transmission-line microwave resonators mediated by an rf SQUID
F. Wulschner, J. Goetz, F. R. Koessel +18
We realize tunable coupling between two superconducting transmission line resonators. The coupling is mediated by a non-hysteretic rf SQUID acting as a flux-tunable mutual inductan…
High cooperativity coupling between a phosphorus donor spin ensemble and a superconducting microwave resonator
Christoph W. Zollitsch, Kai Mueller, David P. Franke +4
We investigate the coupling of an ensemble of phosphorus donors in an isotopically purified Si host lattice interacting with a superconducting coplanar waveguide resonator.…
High cooperativity in coupled microwave resonator ferrimagnetic insulator hybrids
Hans Huebl, Christoph Zollitsch, Johannes Lotze +5
We report the observation of strong coupling between the exchange-coupled spins in gallium-doped yttrium iron garnet and a superconducting coplanar microwave resonator made from Nb…