18

02nd October 2023

Periodic driving (“exciting”) emerged as a powerful technique for engineering quantum systems and realizing nonequilibrium phases of matter. Now, Chong Zu and coworkers reported on effects of prethermalization in a strongly interacting NV-dipolar spin ensembles in diamond (see: Quasi-Floquet Prethermalization in a Disordered Dipolar Spin Ensemble in Diamond, G. He, B. Ye, R. Gong, Z. Liu, K. W. Murch, N.Y. Yao, and C. Zu, Phys. Rev. Lett. 131, 130401 – Published 27 September 2023), which allow to simulate complex quantum dynamics even at room temperature. This can be used to investigate most exciting facets of many-body quantum physics, including the realization of novel phases of matter and the prediction of complex quantum systems. Interestingly, Zu et al. were able to keep their quantum system stable for up to 10 milliseconds (at room temperature), which is a long period of time in the quantum world.

17

24th August 2023

Neuer Text

16

20th July 2023

Diamond shows superior properties for a wide range of technological applications. As 3D integration is required for a variety of applications, hetero-integration of diamond into relevant materials is required. In a recent paper by X. Guo et al. (“Direct-bonded diamond membranes for heterogeneous quantum and electronic technologies”, X. Guo et al., arXiv:2306.04408 [physics.app-ph]) they introduce a technology to directly bond single-crystal diamond membranes to a wide variety of materials like silicon, fused silica, sapphire, thermal oxide, and lithium niobate has been demonstrated. They generate bonded crystalline membranes with thickness as low as 10 nm, sub-nm interfacial regions, and nanometer-scale thickness variability over 200 by 200 μm2 areas and demonstrate methods for integrating high quality factor nanophotonic cavities with the diamond heterostructures. The processes demonstrates a toolkit to synthesize heterogeneous diamond-based hybrid systems for quantum and electronic applications.

15

25th of April 2023

A variety of “spin-qubits” are currently developed, including defects in diamond and silicon, basic ingredients for quantum computer, communication networks and many more. Recently, scientists at the Argonne National Laboratory have discovered a method for introducing spinning electrons as qubits into carbon nanotubes, showing extremely long coherence times of up to 10 microseconds (see: Jia-Shiang Chen et al, Long-lived electronic spin qubits in single-walled carbon nanotubes, Nature Communications (2023). DOI: 10.1038/s41467-023-36031-z). Carbon nano-tubes are made from carbon atoms, have a hollow tubular shape and have a thickness of only about one nanometer. To fix the qubit position on the carbon nano-tube, the authors optimized the atomic structure a bit. These qubits can be integrated into quantum devices and permits many possible ways to read out quantum information. A very important step towards carbon-based quantum technology.

14

11th of March 2023

A variety of “spin-qubits” are currently developed, including defects in diamond and silicon, basic ingredients for quantum computer, communication networks and many more. Recently, scientists at the Argonne National Laboratory have discovered a method for introducing spinning electrons as qubits into carbon nanotubes, showing extremely long coherence times of up to 10 microseconds (see: Jia-Shiang Chen et al, Long-lived electronic spin qubits in single-walled carbon nanotubes, Nature Communications (2023). DOI: 10.1038/s41467-023-36031-z). Carbon nano-tubes are made from carbon atoms, have a hollow tubular shape and have a thickness of only about one nanometer. To fix the qubit position on the carbon nano-tube, the authors optimized the atomic structure a bit. These qubits can be integrated into quantum devices and permits many possible ways to read out quantum information. A very important step towards carbon-based quantum technology.

13

8th OF March 2023

The NDNC provides a unique opportunity for academics and industry professionals to discuss the latest issues and progresses in the field of diamond, carbon, and related materials and their applications. NDNC 2023 is planned in be held in East Lansing, Michigan, USA from 18 to 22 June 2022 (for details see: https://www.ndnc2023.org/)

12

27th of February 2023

Deep-space communications, radio astronomy, radar, MW spectroscopy, and quantum technology (quantum computing, quantum sensing, and quantum communication) require amplification and detection of microwave signals with minimal addition of noise. In a recent paper (“Diamond-based microwave quantum amplifier, A. Sherman et al., Science Advances 8 (49) 2022, DOI: 10.1126/sciadv.ade6527”) Sherman and co-workers describe the operation of diamond based solid-state maser (Microwave Amplification by Stimulated Emission of Radiation (“MASER”) with quantum-limited internal noise at temperatures above liquid nitrogen. This result is based on a previously published paper (“Continuous-wave room-temperature diamond maser, J. D. Breeze et al., Nature 555, p. 493, 2018”) showing a major success of device realization. Diamond based MASER technology will be an important key-development for applications of diamond in quantum science.

11

1st of February 2023

Deep-space communications, radio astronomy, radar, MW spectroscopy, and quantum technology (quantum computing, quantum sensing, and quantum communication) require amplification and detection of microwave signals with minimal addition of noise. In a recent paper (“Diamond-based microwave quantum amplifier, A. Sherman et al., Science Advances 8 (49) 2022, DOI: 10.1126/sciadv.ade6527”) Sherman and co-workers describe the operation of diamond based solid-state maser (Microwave Amplification by Stimulated Emission of Radiation (“MASER”) with quantum-limited internal noise at temperatures above liquid nitrogen. This result is based on a previously published paper (“Continuous-wave room-temperature diamond maser, J. D. Breeze et al., Nature 555, p. 493, 2018”) showing a major success of device realization. Diamond based MASER technology will be an important key-development for applications of diamond in quantum science.

10

20TH OF NOVEmbER 2022

Diamond Foundry has purchased Augsburg Diamond Technology—also known as Audiatec—a manufacturer of diamond wafers based in Augsburg, Germany (see: https://www.onvista.de/news/2022/11-15-eqs-news-wts-advisory-ag-beratung-der-audiatec-bei-der-veraeusserung-saemtlicher-anteile-an-diamond-foundry-37-26065098). “With the acquisition of Audiatec, Diamond Foundry has taken over the technologically leading producer of synthesized, monocrystalline diamond in wafer size,” said a press release from WTS. “In the process used by Audiatec, monocrystalline diamond is deposited on a foreign substrate (heteroepitaxy) using chemical vapor deposition,” it said. “This makes it possible for the first time to synthesize diamond in monocrystalline form on disks with a diameter of up to 100 mm.” Audiatec was founded in 2015 by Dr. Matthias Schreck, Dr. Martin Fischer, and Dr. Stefan Gsell. Schreck and Fischer, its comanaging directors, plan to stay on with the company.

09

12th of NOVEmbER 2022

In a recent paper, McCloskey et al., reported about the development of a new optoelectronic voltage imaging system that overcomes conventional limitations by using nitrogen-vacancy (NV) defects in diamond as charge-sensitive fluorescent reporters. This microscope is for detecting neuronal activities and will be further optimized towards in vitro recording of neurons. Unique is the combination of a) high spatial resolution, b) large spatial scale, and c) complete stability over time. This breakthrough in technology represents a major step towards label-free, large-scale and long-term voltage recording of physical and biological systems, thereby paving the way towards significant improvements in neuroscience and neuropharmacology.

McCloskey, D.J., Dontschuk, N., Stacey, A. et al. A diamond voltage imaging microscope. Nat. Photon. 16, 730–736 (2022). https://doi.org/10.1038/s41566-022-01064-1

08

15th of SepTEMBER 2022

Accurate prediction of the remaining driving range of electric vehicles is difficult because the state-of-the-art sensors for measuring battery current are not accurate enough to estimate the state of charge. This is because the battery current of EVs can reach a maximum of several hundred amperes while the average current is only approximately 10 A, and ordinary sensors do not have an accuracy of several tens of milliamperes while maintaining a dynamic range of several hundred amperes. Therefore, the state of charge has to be estimated with an ambiguity of approximately 10%, which makes the battery usage inefficient.

Hatano and colleagues report in a recent exciting paper (Hatano, Y., Shin, J., Tanigawa, J. et al. High-precision robust monitoring of charge/discharge current over a wide dynamic range for electric vehicle batteries using diamond quantum sensors. Sci Rep 12, 13991 (2022). https://doi.org/10.1038/s41598-022-18106-x) about “high‑precision robust charge/discharge diamond quantum sensors for electric vehicle batteries”. This breakthrough is a milestone for diamond quantum technology as it relates to “e-car technology” with large scale markets involved.

07

14th OF junE 2022

What is “doping by implantation” for conventional semiconductors is “local overgrowth” for diamond.

In a recent paper (see: Selectively buried growth of heavily B doped diamond layers with step-free surfaces in N doped diamond (111) by homoepitaxial lateral growth, K. Kobayashi et al., Applied Surface Science 593, 15 August 2022, 153340, https://www.sciencedirect.com/science/article/pii/S0169433222008959) a novel method to form buried heavily boron (B) doped local structures with atomically smooth surfaces in (111)-oriented diamond based on homoepitaxial lateral growth technique has been introduced.

This new technology can be applied to form diamond contacts (p+ or n+ layers) as well as to generate local nitrogen-vacancy centers by CVD growth of diamond. This substitutes implantation technology, which cannot by applied without heavy damaging the diamond.

The lateral growth

06

2ND OF junE  2022

Tremendous: the application of “effective medium physics” for the realization of diamond laser reflectors will move the field of optical applications of diamond in to high power laser devices and combine the high refraction index with the extraordinary thermal property of diamond.

Congratulations to the team of Marco Loncar
(see:  Diamond mirrors for high-power continuous-wave lasers, NATURE COMMUNICATIONS   (2022) 13:2610   
https://doi.org/10.1038/s41467-022-30335-2).

05

2ND OF AprIL 2022

In a recent paper by E. Bourgeois et al. (“Photoelectric Detection of Nitrogen-Vacancy Centers Magnetic Resonances in Diamond: Role of Charge Exchanges with Other Optoelectrically Active Defects”, in Adv. Quantum Technol. 2022, 2100153) the authors report about photoelectric detection of nitrogen-vacancy (NV) magnetic resonance (PDMR) in diamond. The use of photocurrents instead of optical techniques would offer physical and technical advantages for miniaturized and scalable quantum sensors. However, in this paper, they show that charge exchanges effects between NV centers and acceptor like defects in diamond can cause inversion of sign of the PDMR resonance - an effect which may limit the use of this technique in practical applications. They introduce optical ionizing of the acceptor defects by red light illumination to improve PDMR performances in terms of spin contrast and photoelectric detection rate and shown a significant improvement of the photoelectric spin detection sensitivity. The authors emphasis the importance of defect minimization during shallow nitrogen implantation, which in general is crucial for all diamond-based quantum applications of NV centers.

04

2ND OF AprIL 2022

 After a two years break due to Covid19 the international conference on New Diamond and Nano-Carbons will take place again in Kanazawa, Japan, between 6^th and 9^th of June, 2022
(see: https://www.ndnc2022.org/index.html).
This will be a great restart and address interesting topics in CVD diamond research and developments.

03

7th of DecEMBER 2021

Diamond Foundry announced

(see: https://diamondfoundry.com/pages/future-tech)

the development of single-crystal diamond wafers for semiconductor applications. It is a development that became possible via new plasma reactor technology -which can handle 200 mm single-crystal diamond wafers. These wafers enable advances in RF power technology (5G communications and satellites), in power electronics (used in electric vehicles) and quantum metrology.

Furthermore, Diamond Foundry announced a 850 million USD project in Europe/Spain (see: https://diamondfoundry.com/blogs/the-foundry-journal/d-foundry-ii-spain) where they plan to produce single-crystal diamond chips (start in 2025), with total production ramping to 10 million carats, serving both traditional diamond buyers as well as the semiconductor industries (figure from https://diamondfoundry.com/pages/future-tech).

02

14th of NovEMBER 2021:

A. Lozovoi et al. (Nature Electronics, 2021; 4 (10): 717 DOI: 10.1038/s41928-021-00656-z) applied for the first time single charge excitation/trapping experiments on two neighboring nitrogen-vacancy center in diamond (NV). They demonstrate that they could eject a single hole under laser illumination, allowing the other defect several micrometers away to catch it. The charge state of the “trapping defect” is then altered from negative into neutral via the charge capture. This data reveal that single hole trapping of NV- is about one thousand times more efficient ("giant capture cross-section") than expected. This discovery could pave the way towards a novel quantum information bus effect connecting color center qubits in diamond.

01

30th of SepTEMBER 2021

Ronald Hanson and colleagues present in an interesting review article (see: J. Appl. Phys. 130, 070901 (2021); doi: 10.1063/5.0056534) a summary on quantum networks based on diamond color centers. They identify that diamond color centers already define the state of the art in multi-node entanglement-based networks and in memory-enhanced quantum key distribution. They expect a rapid progress on photonic interfaces and integration of color centers, which will initiate long-distance quantum links which will stimulate new applications like distributed quantum computing. The authors indicate that color centers in diamond may play an essential role in these networks.

Schematic overview of a future large-scale quantum network, consisting of nodes containing optically interfaced qubits (purple) with long coherence times. Photons routed via optical fibers or free-space channels serve as mediators to create entanglement (blue wiggled lines). Local area and trunk backbone quantum repeaters (dark and light red circles, respectively) are used to enable a high entanglement generation rate over large distances, overcoming photon transmission loss. The entangle-ment generation is heralded, meaning that detection of certain photon statistics signals the successful generation of an entangled state that is available to a network user for further processing and applications such as networked quantum computation, quantum secured communication, quantum enhanced sensing, and potential not yet dis-covered tasks.