Ultracold electrons via Near-Threshold Photoemission from Single-Crystal Cu(100)

Abstract

Achieving a low mean transverse energy or temperature of electrons emitted from the photocathode-based electron sources is critical to the development of next-generation and compact X-ray Free Electron Lasers and Ultrafast Electron Diffraction, Spectroscopy and Microscopy experiments. In this paper, we demonstrate a record low mean transverse energy of 5 meV from the cryo-cooled (100) surface of copper using near-threshold photoemission. Further, we also show that the electron energy spread obtained from such a surface is less than 11.5 meV, making it the smallest energy spread electron source known to date: more than an order of magnitude smaller than any existing photoemission, field emission or thermionic emission based electron source. Our measurements also shed light on the physics of electron emission and show how the energy spread at few meV scale energies is limited by both the temperature and the vacuum density of states.

References in corpus (7)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• JDFTx: software for joint density-functional theory
• Laser ARPES, the sudden approximation, and quasiparticle-like peaks in Bi2Sr2CaCu2O8+delta
• Ultrafast Relativistic Electron Nanoprobes
• A One-Step Model of Photoemission from Single Crystal Surfaces
• Development of a 3-D energy-momentum analyzer for meV-scale energy electrons

Cited by in corpus (12)

• A single-crystal alkali antimonide photocathode: high efficiency in the ultra-thin limit
• New spin-polarized electron source based on alkali-antimonide photocathode
• A kiloelectron-volt ultrafast electron micro-diffraction apparatus using low emittance semiconductor photocathodes
• Near-monochromatic tuneable cryogenic niobium electron field emitter
• Versatile, high brightness, cryogenic photoinjector electron source
• Inelastic Electron Scattering at a Single-Beam Structured Light Wave
• Spectral Emission Properties of a Nitrogen-doped Diamond(001) Photocathode: Hot Electron Transport and Transverse Momentum Filtering
• Point-to-Point Coulomb Effects in High Brightness Photoelectron Beamlines for Ultrafast Electron Diffraction
• Nanosecond Photoemission near the Potential Barrier of a Schottky Emitter
• Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter
• Revealing the (111) surface electronic structure of epitaxially grown Na${}_2$KSb photocathode
• Emittance Mapping in rf Guns