Garett Reichenbach | Searcharxiv

arXiv2026

Amplification of valley polarization in an hBN-separated MoSe2-WSe2 heterostructure

Transition metal dichalcogenide heterostructures host long-lived interlayer excitons in the +K and -K valleys that can encode long-lived valley polarization. We investigated the low-temperature valley polarization dynamics in an MoSe2-bilayer hBN-WSe2 heterostructure. The bilayer hBN spacer results in an interlayer exciton lifetime exceeding 2 μs and an anomalous valley polarization amplification effect. Our theoretical model shows that this amplification results from the long exciton lifetime and exciton-exciton interactions. This work sets the stage for long-lived interlayer excitons to be used in nonlinear valleytronic transistors and amplifiers.

cond-mat.mes-hall↗

arXiv2023

magnetoARPES: Angle Resolved Photoemission Spectroscopy with Magnetic Field Control

Angle-Resolved Photoemission Spectroscopy (ARPES) is a premier technique for understanding the electronic excitations in conductive, crystalline matter, in which the induced photocurrent is collected and dispersed in energy and angle of emission to reveal the energy- and momentum-dependent single particle spectral function $A(\mathbf{k},ω)$. So far, ARPES in a magnetic field has been precluded due to the need to preserve the electron paths between the sample and detector. In this paper we report progress towards "magnetoARPES", a variant of ARPES that can be conducted in a magnetic field. It is achieved by applying a microscopic probe beam ($\lesssim$ 10 $μ$m ) to a thinned sample mounted upon a special sample holder that generates magnetic field confined to a thin layer near the sample surface. In this geometry we could produce ARPES in magnetic fields up to around $\pm$ 100 mT. The magnetic fields can be varied from purely in-plane to nearly purely out-of-plane, by scanning the probe beam across different parts of the device. We present experimental and simulated data for graphene to explore the aberrations induced by the magnetic field. These results demonstrate the viability of the magnetoARPES technique for exploring symmetry breaking effects in weak magnetic fields.

cond-mat.str-el↗