Quantum Transport in Two-Dimensional Materials

Quantum transport in atomically thin systems has emerged as a vibrant field, exploring how electrons traverse two-dimensional (2D) landscapes under quantum‐mechanical constraints. Materials such as graphene, transition metal dichalcogenides (TMDCs) and novel heterostructures exploit reduced dimensionality to reveal phenomena absent in bulk. Electrons in these sheets can move in a ballistic regime, encountering minimal scattering over micrometre scales, and manifest conductance in discrete units of the fundamental quantum of conductance. Perpendicular magnetic fields give rise to Landau quantisation and quantum Hall plateaux, while spin–orbit coupling and broken inversion symmetry introduce coupled spin and valley dynamics. Quantum dots and nanoribbons etched or gate‐defined in 2D crystals serve as tunable confinement regions, enabling observation of Coulomb blockade and single‐level transport. The interplay of contact engineering, substrate choice and dielectric environment further governs low‐temperature transport, facilitating the observation of Shubnikov–de Haas oscillations, valley‐Hall currents and gate‐tunable quantised conductance. Collectively, these effects underpin advances towards spintronics, valleytronics and quantum information processing, promising low‐power electronics and new platforms for manipulating quantum degrees of freedom.

Research from Nature Portfolio

Recent studies have mapped the subtleties of quantum transport in layered TMDCs. Even–odd layer magnetotransport measurements in few‐layer disulfides reveal that inversion symmetry dictates whether spin or valley Zeeman effects dominate Shubnikov–de Haas oscillations and quantum Hall plateaux, offering insight into multi‐valley band structures across different thicknesses. Monolayer MoS₂ has been shown to host intrinsic valley Hall transport: nonlocal resistance measurements exhibit a cubic scaling with local resistance and persist up to room temperature, confirming topological valley currents without extrinsic symmetry breaking. In high‐mobility monolayer MoS₂ devices, well‐developed quantised conductance steps at zero magnetic field have been extracted, with sub‐band spacings in the millielectronvolt range and g‐factors consistent with valley‐Zeeman splitting, highlighting the potential for spin‐ and valley‐selective transport.

Quantum Transport in Two-Dimensional Materials publication trend

The graph below shows the total number of articles in quantum transport in two-dimensional materials across all publications each year (not limited to Nature Index journals).

Technical terms

Quantised conductance: Discrete steps in electrical conductance occurring in units of 2e²/h or e²/h in one‐dimensional channels or narrow constrictions under quantum‐coherent transport.

Shubnikov–de Haas oscillations: Periodic variations in magnetoresistance observed at low temperatures due to Landau quantisation of cyclotron orbits in two‐dimensional electron systems.

Coulomb blockade: Suppression of electron transport through a small quantum dot or nanoparticle when the charging energy exceeds thermal energy, resulting in discrete conductance peaks.

Valley degree of freedom: An electronic quantum number corresponding to local minima in the conduction or valence band at inequivalent points (valleys) in momentum space.

Spin–orbit coupling: Interaction between an electron’s spin and its motion in an electric field, leading to energy band splitting and enabling spin‐dependent transport phenomena.

References

1. Non‐Destructive Low‐Temperature Contacts to MoS2 Nanoribbon and Nanotube Quantum Dots. Advanced Materials (2023).
2. Anomalous conductance quantization of a one-dimensional channel in monolayer WSe2. npj 2D Materials and Applications (2023).
3. Universal low-temperature Ohmic contacts for quantum transport in transition metal dichalcogenides. 2D Materials (2016).
4. Even–odd layer-dependent magnetotransport of high-mobility Q-valley electrons in transition metal disulfides. Nature Communications (2016).
5. Intrinsic valley Hall transport in atomically thin MoS2. Nature Communications (2019).