First observation of quantum oscillations by transport measurements in semi-destructive pulsed magnetic fields up to 125 T

TL;DR

The study tackles the challenge of performing transport measurements at ultra-high magnetic fields where conventional destructive methods are limited. It introduces a microwave two-point transport technique compatible with semi-destructive pulsed fields up to 125 T, incorporating rigorous shielding and a dedicated heating model to interpret temperature rise during rapid field changes. The authors validate their approach by reproducing the metal-insulator transition in InAs at the quantum limit and by achieving the first observation of Shubnikov-de-Haas oscillations in the Weyl semimetal WTe2 above 100 T, including high-field magnetic-breakdown phenomena. This work demonstrates the viability of megagauss-field transport experiments and lays the groundwork for extending measurements toward ~200 T, enabling new investigations of quantum materials under extreme magnetic fields.

Abstract

High magnetic fields have proven instrumental in exploring the physical properties of condensed matter, leading to groundbreaking discoveries such as the quantum Hall effect in 2D heterostructures and quantum oscillations in cuprate superconductors. The ability to conduct precise measurements at progressively higher magnetic fields continues to push the frontiers of knowledge and enable new discoveries. In this work, we present the development of a microwave technique for performing two-point transport measurements in semi-destructive pulsed magnetic fields (up to 125 T) and at low temperatures (down to 1.5 K) with unprecedented sensitivity. This new setup was tested on a variety of samples. We present results on the metal-insulator transition in InAs and we report notably the first observation of Shubnikov-de-Haas oscillations in WTe$_{2}$ at magnetic fields beyond 100 T.

Figures (4)

• Figure 1: a) Magnetic field as a function of time for two different pulse modes; non-destructive in grey (14 kV) and semi-destructive in blue (40 kV). Inset: Measurement of the trigger noise coming from the spark-gap switches using a twisted pair soldered at its end and attenuators to protect the data acquisition card. b) Sectional view of the cryostat showing (1) probe port, (2) nitrogen bath, (3) helium bath, (4) insulation vacuum, (5) polycarbonate extensions, and (6) single-turn coil. The experimental sample space has a diameter of 3.1 mm.
• Figure 2: Block diagram of the microwave measurements. The circuit is separated in three main blocks. Top: pick-up acquisition card (RedPitaya Stemlab 125-14) with attenuator, filter and limiter. Middle: the signal acquisition data acquisition card (Teledyne SP devices card ADQ7) with filters, attenuators, pre-amplifiers and limiter. Bottom: the generator (a Windfreak synthUSB3) with filter, attenuator and limiter. The three blocks are connected to the probe through double shielded coaxial cables. The correspondence between the symbols is shown in the legend box.
• Figure 3: A comparison of the resistance of InAs measured in conventional pulsed magnetic fields (dashed lines) at $T$=4.2 K (black), 10 K (blue), and 14 K (red) with that measured in the megagauss (MG) installation (solid lines) at 14 kV (black) and 40 kV (semi-destructive in blue). The base temperature before the pulse was $T$=4.2 K. The non-destructive megagauss data at 14 kV matches closely with the conventional pulsed field measurement at $T$=4.2 K. During the semi-destructive experiment at 40 kV (blue), the sample's temperature rises at the beginning of the pulse.
• Figure 4: Resistance of WTe$_{2}$ as a function of magnetic field. a) Comparison between non-destructive megagauss (MG) experiment (solid black line) and conventional pulse magnetic field (dashed red line) at $T$=4.2 K. The data are shifted for clarity. Inset: Fourier transform of the quantum oscillations observed in megagauss. The observed frequencies are in excellent agreement with published data Linnartz2022. b) Measurement in the semi-destructive mode at 40 kV (solid blue line) showing quantum oscillations up to 125 T. The base temperature before the pulse was $T$=2.5 K. The dashed line corresponds to measurement in the conventional pulsed field at $T$=20 K for comparison (the data are shifted for clarity). Note the reproducibility of the data at 40 kV during the rise above 95 T and the fall of the field pulse. Data for the rise of the field below 95 T are noisy because of the trigger noise. Inset: Quantum oscillations as a function of magnetic field with the spline background subtracted. c) Time evolution of the temperature calculated from equation \ref{['Equation1']} during a semi-destrutive pulse up to 125 T (orange line). The grey line shows the corresponding time dependence of the magnetic field. The temperature rises immediately at the beginning of the pulse, when both d$B$/d$t$ reaches its maximum and the resistivity is at a minimum. It then exhibits a plateau at $T$=21 K during the rise and the fall of the magnetic field (see also ref. Zimmerer2019). In this regime, dissipation remains low due to the large magnetoresistance of WTe$_2$.