-
Intrinsic Spin Transport in a Topological Insulator Thin Film
Authors:
Sharadh Jois,
Gregory M. Stephen,
Nick Blumenschein,
Patrick J. Taylor,
Aubrey T. Hanbicki,
Adam L. Friedman
Abstract:
Topological insulators (TIs) are intriguing materials for advanced computing applications based on spintronics because they can host robust spin effects. For instance, TIs have intrinsically large spin generation enabled by their large spin-orbit coupling. Furthermore, topological surface states (TSS) with spin-momentum locking and Dirac dispersion lead to long spin diffusion. Future spintronic de…
▽ More
Topological insulators (TIs) are intriguing materials for advanced computing applications based on spintronics because they can host robust spin effects. For instance, TIs have intrinsically large spin generation enabled by their large spin-orbit coupling. Furthermore, topological surface states (TSS) with spin-momentum locking and Dirac dispersion lead to long spin diffusion. Future spintronic device technology will require scalable film growth of high-quality material. We grow epitaxial films of Bi$_{1-x}$Sb$_x$Te$_{3-y}$Se$_y$ (BSTS, $x = 0.58, y = 1$) and confirm the gapless band structure with optimal doping using angle-resolved photoelectron spectra. The temperature dependence of longitudinal resistivity shows bulk transport is suppressed as temperature is decreased, and at low temperature surface transport dominates. We evaluate the spin transport properties in BSTS without using ferromagnetic tunnel contacts via a non-local resistance experiment as a function of temperature and applied charge current. As expected, these experiments reveal the necessity of decreasing the bulk conduction to best enhance the spin transport. In the TSS, we find high efficiency of charge-to-spin conversion (spin Hall angle, $θ_{SH} \approx 1$) and spin diffusion over several microns. Further development of high-quality TIs will make them viable candidates for efficient and lossless spintronics.
△ Less
Submitted 10 March, 2025; v1 submitted 6 March, 2025;
originally announced March 2025.
-
Benchmarking the design of the cryogenics system for the underground argon in DarkSide-20k
Authors:
DarkSide-20k Collaboration,
:,
F. Acerbi,
P. Adhikari,
P. Agnes,
I. Ahmad,
S. Albergo,
I. F. M. Albuquerque,
T. Alexander,
A. K. Alton,
P. Amaudruz,
M. Angiolilli,
E. Aprile,
R. Ardito,
M. Atzori Corona,
D. J. Auty,
M. Ave,
I. C. Avetisov,
O. Azzolini,
H. O. Back,
Z. Balmforth,
A. Barrado Olmedo,
P. Barrillon,
G. Batignani,
P. Bhowmick
, et al. (294 additional authors not shown)
Abstract:
DarkSide-20k (DS-20k) is a dark matter detection experiment under construction at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It utilises ~100 t of low radioactivity argon from an underground source (UAr) in its inner detector, with half serving as target in a dual-phase time projection chamber (TPC). The UAr cryogenics system must maintain stable thermodynamic conditions throughout t…
▽ More
DarkSide-20k (DS-20k) is a dark matter detection experiment under construction at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It utilises ~100 t of low radioactivity argon from an underground source (UAr) in its inner detector, with half serving as target in a dual-phase time projection chamber (TPC). The UAr cryogenics system must maintain stable thermodynamic conditions throughout the experiment's lifetime of over 10 years. Continuous removal of impurities and radon from the UAr is essential for maximising signal yield and mitigating background. We are developing an efficient and powerful cryogenics system with a gas purification loop with a target circulation rate of 1000 slpm. Central to its design is a condenser operated with liquid nitrogen which is paired with a gas heat exchanger cascade, delivering a combined cooling power of more than 8 kW. Here we present the design choices in view of the DS-20k requirements, in particular the condenser's working principle and the cooling control, and we show test results obtained with a dedicated benchmarking platform at CERN and LNGS. We find that the thermal efficiency of the recirculation loop, defined in terms of nitrogen consumption per argon flow rate, is 95 % and the pressure in the test cryostat can be maintained within $\pm$(0.1-0.2) mbar. We further detail a 5-day cool-down procedure of the test cryostat, maintaining a cooling rate typically within -2 K/h, as required for the DS-20k inner detector. Additionally, we assess the circuit's flow resistance, and the heat transfer capabilities of two heat exchanger geometries for argon phase change, used to provide gas for recirculation. We conclude by discussing how our findings influence the finalisation of the system design, including necessary modifications to meet requirements and ongoing testing activities.
△ Less
Submitted 19 February, 2025; v1 submitted 26 August, 2024;
originally announced August 2024.
-
A tunable photonic band gap resonator for axion dark matter searches
Authors:
Samantha M. Lewis,
Dillon T. Goulart,
Mirelys Carcana Barbosa,
Shriram Jois,
Alexander F. Leder,
Aarav M. Sindhwad,
Isabella Urdinaran,
Karl van Bibber
Abstract:
Axions are a well-motivated dark matter candidate particle. Haloscopes aim to detect axions in the galactic halo by measuring the photon signal resulting from axions interacting with a strong magnetic field. Existing haloscopes are primarily targeting axion masses which produce microwave-range photons and rely on microwave resonators to enhance the signal power. Only a limited subset of resonator…
▽ More
Axions are a well-motivated dark matter candidate particle. Haloscopes aim to detect axions in the galactic halo by measuring the photon signal resulting from axions interacting with a strong magnetic field. Existing haloscopes are primarily targeting axion masses which produce microwave-range photons and rely on microwave resonators to enhance the signal power. Only a limited subset of resonator modes are useful for this process, and current cylindrical-style cavities suffer from mode mixing and crowding from other fundamental modes. The majority of these modes can be eliminated by using photonic band gap (PBG) resonators. The band gap behavior of these structures allows for a resonator with mode selectivity based on frequency. We present results from the first tunable PBG resonator, a proof-of-concept design with a footprint compatible with axion haloscopes. We have thoroughly characterized the tuning range of two versions of the structure and report the successful confinement of the operating TM$_{010}$ (transverse magnetic) mode and the elimination of all transverse electric modes within the tuning range.
△ Less
Submitted 20 August, 2026; v1 submitted 7 August, 2024;
originally announced August 2024.
-
Axion Dark Matter eXperiment: Run 1A Analysis Details
Authors:
C. Boutan,
B. H. LaRoque,
E. Lentz,
N. S. Oblath,
M. S. Taubman,
J. Tedeschi,
J. Yang,
A. M. Jones,
T. Braine,
N. Crisosto,
L. J Rosenberg,
G. Rybka,
D. Will,
D. Zhang,
S. Kimes,
R. Ottens,
C. Bartram,
D. Bowring,
R. Cervantes,
A. S. Chou,
S. Knirck,
D. V. Mitchell,
A. Sonnenschein,
W. Wester,
R. Khatiwada
, et al. (28 additional authors not shown)
Abstract:
The ADMX collaboration gathered data for its Run 1A axion dark matter search from January to June 2017, scanning with an axion haloscope over the frequency range 645-680 MHz (2.66-2.81 ueV in axion mass) at DFSZ sensitivity. The resulting axion search found no axion-like signals comprising all the dark matter in the form of a virialized galactic halo over the entire frequency range, implying lower…
▽ More
The ADMX collaboration gathered data for its Run 1A axion dark matter search from January to June 2017, scanning with an axion haloscope over the frequency range 645-680 MHz (2.66-2.81 ueV in axion mass) at DFSZ sensitivity. The resulting axion search found no axion-like signals comprising all the dark matter in the form of a virialized galactic halo over the entire frequency range, implying lower bound exclusion limits at or below DFSZ coupling at the 90% confidence level. This paper presents expanded details of the axion search analysis of Run 1A, including review of relevant experimental systems, data-taking operations, preparation and interpretation of raw data, axion search methodology, candidate handling, and final axion limits.
△ Less
Submitted 27 December, 2023;
originally announced December 2023.
-
Directionality of nuclear recoils in a liquid argon time projection chamber
Authors:
The DarkSide-20k Collaboration,
:,
P. Agnes,
I. Ahmad,
S. Albergo,
I. F. M. Albuquerque,
T. Alexander,
A. K. Alton,
P. Amaudruz,
M. Atzori Corona,
M. Ave,
I. Ch. Avetisov,
O. Azzolini,
H. O. Back,
Z. Balmforth,
A. Barrado-Olmedo,
P. Barrillon,
A. Basco,
G. Batignani,
V. Bocci,
W. M. Bonivento,
B. Bottino,
M. G. Boulay,
J. Busto,
M. Cadeddu
, et al. (243 additional authors not shown)
Abstract:
The direct search for dark matter in the form of weakly interacting massive particles (WIMP) is performed by detecting nuclear recoils (NR) produced in a target material from the WIMP elastic scattering. A promising experimental strategy for direct dark matter search employs argon dual-phase time projection chambers (TPC). One of the advantages of the TPC is the capability to detect both the scint…
▽ More
The direct search for dark matter in the form of weakly interacting massive particles (WIMP) is performed by detecting nuclear recoils (NR) produced in a target material from the WIMP elastic scattering. A promising experimental strategy for direct dark matter search employs argon dual-phase time projection chambers (TPC). One of the advantages of the TPC is the capability to detect both the scintillation and charge signals produced by NRs. Furthermore, the existence of a drift electric field in the TPC breaks the rotational symmetry: the angle between the drift field and the momentum of the recoiling nucleus can potentially affect the charge recombination probability in liquid argon and then the relative balance between the two signal channels. This fact could make the detector sensitive to the directionality of the WIMP-induced signal, enabling unmistakable annual and daily modulation signatures for future searches aiming for discovery. The Recoil Directionality (ReD) experiment was designed to probe for such directional sensitivity. The TPC of ReD was irradiated with neutrons at the INFN Laboratori Nazionali del Sud, and data were taken with 72 keV NRs of known recoil directions. The direction-dependent liquid argon charge recombination model by Cataudella et al. was adopted and a likelihood statistical analysis was performed, which gave no indications of significant dependence of the detector response to the recoil direction. The aspect ratio R of the initial ionization cloud is estimated to be 1.037 +/- 0.027 and the upper limit is R < 1.072 with 90% confidence level
△ Less
Submitted 28 July, 2023;
originally announced July 2023.
-
Measuring the Electronic Bandgap of Carbon Nanotube Networks in Non-ideal p-n Diodes
Authors:
Gideon Oyibo,
Thomas Barrett,
Sharadh Jois,
Jeffrey L. Blackburn,
Ji Ung Lee
Abstract:
The measurement of the bandgap in quasi-one dimensional materials such as carbon nanotubes is challenging due to its dimensionality. In this work, we measure the electronic bandgap of networks of polymer-wrapped semiconducting single-walled carbon nanotubes (s-SWCNTs) using non-ideal p-n diodes. Using these diodes, we measure the electronic bandgap and excitonic levels of different polymer-wrapped…
▽ More
The measurement of the bandgap in quasi-one dimensional materials such as carbon nanotubes is challenging due to its dimensionality. In this work, we measure the electronic bandgap of networks of polymer-wrapped semiconducting single-walled carbon nanotubes (s-SWCNTs) using non-ideal p-n diodes. Using these diodes, we measure the electronic bandgap and excitonic levels of different polymer-wrapped s-SWCNTs with varying diameters: arc discharge (~1.55nm), (7,5) (0.83nm), and (6,5) (0.76nm). Our values are consistent with theoretical predictions, providing insight into the fundamental properties of networks of s-SWCNTs.
△ Less
Submitted 12 December, 2022;
originally announced December 2022.
-
PlomBOX -- development of a low-cost CMOS device for environmental monitoring
Authors:
A. Aguilar-Arevalo,
E. Alba Posse,
M. Alvarez,
H. Arnaldi,
H. Asorey,
X. Bertou,
A. Colque,
A. Deisting,
A. Dias,
J. C. D'Olivo,
F. Favela-Pérez,
Y. Gándola,
E. A. Garcés,
J. Gasulla,
M. Gómez Berisso,
A. González Muñoz,
J. O. Guerra-Pulido,
S. Gutierrez,
S. Jois,
J. Lipovetzky,
J. Lovera,
M. B. Lovino,
D. J. Marín-Lámbarri,
L. Marpegan,
D. Martín
, et al. (14 additional authors not shown)
Abstract:
This paper reports on the development of a novel CMOS device employing lead-sensing bacteria to assay lead in drinking water. The objective of the PlomBOX project is to develop a low-cost sensor (£10) which can expedite access to on-demand assay methods and thus help mitigate lead intake through contaminated drinking water. The project follows three development paths: a) Certain bacteria can fluor…
▽ More
This paper reports on the development of a novel CMOS device employing lead-sensing bacteria to assay lead in drinking water. The objective of the PlomBOX project is to develop a low-cost sensor (£10) which can expedite access to on-demand assay methods and thus help mitigate lead intake through contaminated drinking water. The project follows three development paths: a) Certain bacteria can fluoresce or change colour when in the presence of lead. A genetically modified strain of Escherichia coli sensitive to lead concentrations up to 10 ppb is being developed. This constitutes the biosensor that fluoresces in proportion to the presence of lead. b) Bacteria response is imaged using a microprocessor (ESP32) with a camera module. This constitutes the optical metrology component of the PlomBOX. c) Data acquisition and control of the PlomBOX is achieved through a Bluetooth connection with the PlomApp, a custom-developed mobile phone application. Data are sent from the PlomApp to a database where a bespoke automated analysis software provides a result of the lead concentration in a sample of water. This paper reports on the instrumentation challenges of developing the electronics for the PlomBOX and on the first prototype.
△ Less
Submitted 10 January, 2022;
originally announced January 2022.
-
Search for "Invisible" Axion Dark Matter in the $3.3\text{-}4.2~μ$eV Mass Range
Authors:
ADMX Collaboration,
C. Bartram,
T. Braine,
E. Burns,
R. Cervantes,
N. Crisosto,
N. Du,
H. Korandla,
G. Leum,
P. Mohapatra,
T. Nitta,
L. J Rosenberg,
G. Rybka,
J. Yang,
John Clarke,
I. Siddiqi,
A. Agrawal,
A. V. Dixit,
M. H. Awida,
A. S. Chou,
M. Hollister,
S. Knirck,
A. Sonnenschein,
W. Wester,
J. R. Gleason
, et al. (27 additional authors not shown)
Abstract:
We report the results from a haloscope search for axion dark matter in the $3.3\text{-}4.2~μ$eV mass range. This search excludes the axion-photon coupling predicted by one of the benchmark models of "invisible" axion dark matter, the KSVZ model. This sensitivity is achieved using a large-volume cavity, a superconducting magnet, an ultra low noise Josephson parametric amplifier, and sub-Kelvin temp…
▽ More
We report the results from a haloscope search for axion dark matter in the $3.3\text{-}4.2~μ$eV mass range. This search excludes the axion-photon coupling predicted by one of the benchmark models of "invisible" axion dark matter, the KSVZ model. This sensitivity is achieved using a large-volume cavity, a superconducting magnet, an ultra low noise Josephson parametric amplifier, and sub-Kelvin temperatures. The validity of our detection procedure is ensured by injecting and detecting blind synthetic axion signals.
△ Less
Submitted 29 December, 2021; v1 submitted 12 October, 2021;
originally announced October 2021.
-
Axion Dark Matter eXperiment: Detailed Design and Operations
Authors:
R. Khatiwada,
D. Bowring,
A. S. Chou,
A. Sonnenschein,
W. Wester,
D. V. Mitchell,
T. Braine,
C. Bartram,
R. Cervantes,
N. Crisosto,
N. Du,
S. Kimes,
L. J Rosenberg,
G. Rybka,
J. Yang,
D. Will,
G. Carosi,
N. Woollett,
S. Durham,
L. D. Duffy,
R. Bradley,
C. Boutan,
M. Jones,
B. H. LaRoque,
N. S. Oblath
, et al. (26 additional authors not shown)
Abstract:
Axion Dark Matter eXperiment (ADMX) ultra low noise haloscope technology has enabled the successful completion of two science runs (1A and 1B) that looked for dark matter axions in the $2.66$ to $3.1$ $μ$eV mass range with Dine-Fischler-Srednicki-Zhitnisky (DFSZ) sensitivity Ref. [1,2]. Therefore, it is the most sensitive axion search experiment to date in this mass range. We discuss the technolog…
▽ More
Axion Dark Matter eXperiment (ADMX) ultra low noise haloscope technology has enabled the successful completion of two science runs (1A and 1B) that looked for dark matter axions in the $2.66$ to $3.1$ $μ$eV mass range with Dine-Fischler-Srednicki-Zhitnisky (DFSZ) sensitivity Ref. [1,2]. Therefore, it is the most sensitive axion search experiment to date in this mass range. We discuss the technological advances made in the last several years to achieve this sensitivity, which includes the implementation of components, such as state-of-the-art quantum limited amplifiers and a dilution refrigerator. Furthermore, we demonstrate the use of a frequency tunable Microstrip Superconducting Quantum Interference Device (SQUID) Amplifier (MSA), in Run 1A, and a Josephson Parametric Amplifier (JPA), in Run 1B, along with novel analysis tools that characterize the system noise temperature.
△ Less
Submitted 30 September, 2020;
originally announced October 2020.
-
Extended Search for the Invisible Axion with the Axion Dark Matter Experiment
Authors:
T. Braine,
R. Cervantes,
N. Crisosto,
N. Du,
S. Kimes,
L. J Rosenberg,
G. Rybka,
J. Yang,
D. Bowring,
A. S. Chou,
R. Khatiwada,
A. Sonnenschein,
W. Wester,
G. Carosi,
N. Woollett,
L. D. Duffy,
R. Bradley,
C. Boutan,
M. Jones,
B. H. LaRoque,
N. S. Oblath,
M. S. Taubman,
J. Clarke,
A. Dove,
A. Eddins
, et al. (17 additional authors not shown)
Abstract:
This paper reports on a cavity haloscope search for dark matter axions in the galactic halo in the mass range $2.81$-$3.31$ $μeV$. This search excludes the full range of axion-photon coupling values predicted in benchmark models of the invisible axion that solve the strong CP problem of quantum chromodynamics, and marks the first time a haloscope search has been able to search for axions at mode c…
▽ More
This paper reports on a cavity haloscope search for dark matter axions in the galactic halo in the mass range $2.81$-$3.31$ $μeV$. This search excludes the full range of axion-photon coupling values predicted in benchmark models of the invisible axion that solve the strong CP problem of quantum chromodynamics, and marks the first time a haloscope search has been able to search for axions at mode crossings using an alternate cavity configuration. Unprecedented sensitivity in this higher mass range is achieved by deploying an ultra low-noise Josephson parametric amplifier as the first stage signal amplifier.
△ Less
Submitted 1 November, 2019; v1 submitted 18 October, 2019;
originally announced October 2019.
-
Direct Measurement of the Electron Beam Intensity Profile via Carbon Nanotube Tomography
Authors:
Matthew Zotta,
Sharadh Jois,
Prathamesh Dhakras,
Miguel Rodriguez,
Ji Ung Lee
Abstract:
Electron microscopes have been improved to achieve ever smaller beam spots, a key parameter that determines the instrument's resolution. The techniques to measure the size of the beam, however, have not progressed to the same degree. There is an on-going need to develop detection technologies that can potentially characterize the smallest electron beam to further improve the capabilities of these…
▽ More
Electron microscopes have been improved to achieve ever smaller beam spots, a key parameter that determines the instrument's resolution. The techniques to measure the size of the beam, however, have not progressed to the same degree. There is an on-going need to develop detection technologies that can potentially characterize the smallest electron beam to further improve the capabilities of these instruments. We report on a new electron beam detector based on a single-walled carbon nanotube. Nanotubes are atomically smooth, have a well-defined diameter that is similar in size to the finest electron probes and can be used to directly measure the beam profile. By scanning the beam at different angles to the nanotube, we can accurately determine the spatial profile of an electron beam by applying tomographic reconstruction techniques.
△ Less
Submitted 7 February, 2019;
originally announced February 2019.
-
Piezoelectrically Tuned Multimode Cavity Search for Axion Dark Matter
Authors:
C. Boutan,
M. Jones,
B. H. LaRoque,
N. S. Oblath,
R. Cervantes,
N. Du,
N. Force,
S. Kimes,
R. Ottens,
L. J. Rosenberg,
G. Rybka,
J. Yang,
G. Carosi,
N. Woollett,
D. Bowring,
A. S. Chou,
R. Khatiwada,
A. Sonnenschein,
W. Wester,
R. Bradley,
E. J. Daw,
A. Agrawal,
A. V. Dixit,
J. Clarke,
S. R. O'Kelley
, et al. (9 additional authors not shown)
Abstract:
The $μ$eV axion is a well-motivated extension to the standard model. The Axion Dark Matter eXperiment (ADMX) collaboration seeks to discover this particle by looking for the resonant conversion of dark-matter axions to microwave photons in a strong magnetic field. In this Letter, we report results from a pathfinder experiment, the ADMX "Sidecar," which is designed to pave the way for future, highe…
▽ More
The $μ$eV axion is a well-motivated extension to the standard model. The Axion Dark Matter eXperiment (ADMX) collaboration seeks to discover this particle by looking for the resonant conversion of dark-matter axions to microwave photons in a strong magnetic field. In this Letter, we report results from a pathfinder experiment, the ADMX "Sidecar," which is designed to pave the way for future, higher mass, searches. This testbed experiment lives inside of and operates in tandem with the main ADMX experiment. The Sidecar experiment excludes masses in three widely spaced frequency ranges (4202-4249, 5086-5799, and 7173-7203 MHz). In addition, Sidecar demonstrates the successful use of a piezoelectric actuator for cavity tuning. Finally, this publication is the first to report data measured using both the TM$_{010}$ and TM$_{020}$ modes.
△ Less
Submitted 3 January, 2019;
originally announced January 2019.
-
A Search for Invisible Axion Dark Matter with the Axion Dark Matter Experiment
Authors:
N. Du,
N. Force,
R. Khatiwada,
E. Lentz,
R. Ottens,
L. J Rosenberg,
G. Rybka,
G. Carosi,
N. Woolett,
D. Bowring,
A. S. Chou,
A. Sonnenschein,
W. Wester,
C. Boutan,
N. S. Oblath,
R. Bradley,
E. J. Daw,
A. V. Dixit,
J. Clarke,
S. R. O'Kelley,
N. Crisosto,
J. R. Gleason,
S. Jois,
P. Sikivie,
I. Stern
, et al. (3 additional authors not shown)
Abstract:
This Letter reports results from a haloscope search for dark matter axions with masses between 2.66 and 2.81 $μ$eV. The search excludes the range of axion-photon couplings predicted by plausible models of the invisible axion. This unprecedented sensitivity is achieved by operating a large-volume haloscope at sub-kelvin temperatures, thereby reducing thermal noise as well as the excess noise from t…
▽ More
This Letter reports results from a haloscope search for dark matter axions with masses between 2.66 and 2.81 $μ$eV. The search excludes the range of axion-photon couplings predicted by plausible models of the invisible axion. This unprecedented sensitivity is achieved by operating a large-volume haloscope at sub-kelvin temperatures, thereby reducing thermal noise as well as the excess noise from the ultra-low-noise SQUID amplifier used for the signal power readout. Ongoing searches will provide nearly definitive tests of the invisible axion model over a wide range of axion masses.
△ Less
Submitted 17 April, 2018; v1 submitted 16 April, 2018;
originally announced April 2018.