A time- and angle-resolved photoemission spectroscopy with probe photon energy up to 6.7 eV

Abstract

We present the development of a time-and angle-resolved photoemission spectroscopy based on a Yb-based femtosecond laser and a hemispherical electron analyzer. The energy of the pump photon is tunable between 1.4 and 1.9 eV, and the pulse duration is around 30 fs. We use a KBe2BO3F2 non-linear optical crystal to generate probe pulses, of which the photon energy is up to 6.7 eV, and obtain an overall time resolution of 1 ps and energy resolution of 18 meV. In addition, β-BaB2O4 crystals are used to generate alternative probe pulses at 6.05 eV, giving an overall time resolution of 130 fs and energy resolution of 19 meV. We illustrate the performance of the system with representative data on several samples (Bi2Se3, YbCd2Sb2, FeSe). arXiv:2003.00515v1 [cond-mat.str-el] 1 Mar 2020 * wentaozhang@sjtu.edu.cn 1 A. Damascelli, Z. Hussain, and Z.-X. Shen, Rev. Mod. Phys. 75, 473 (2003).

Dirac Surface States in Intrinsic Magnetic Topological Insulators EuSn2As2 and Li1, Gao2, Duan3 et al. 2019Phys. Rev. X259101142View full textAdd to dashboardCite

“…Photoelectrons were collected by a Scienta DA30L-8000R analyzer. The overall time resolution and energy resolution are 130 fs and 19 meV respectively [45]. Sample was cleaved at a pressure better than 3×10 11 torr at 4 K.…”

An Integrated Quantum Material Testbed with Multi-Resolution Photoemission Spectroscopy

“…A cross-correlation is extracted from 1 eV above E F and is fitted to an exponential function convolved with a Gaussian resolution function (Figure 3(d)). The fitting yields a FWHM = 35 ± 1 fs, which is to our knowledge the best time resolution among all trARPES setups using solid-crystal-based frequency upconversion 16,18,25,[32][33][34][35] . This time resolution is obtained using a 150 µm-thick BBO for second harmonic generation (SHG), and a 50 µm-thick BBO for fourth harmonic generation (FHG).…”

Extreme ultraviolet time- and angle-resolved photoemission setup with 21.5 meV resolution using high-order harmonic generation from a turn-key Yb:KGW amplifier

“…trARPES was first demonstrated using probe pulses derived from perturbative harmonic generation in nonlinear crystals, such as BaB 2 O 4 (BBO) [14][15][16][17][18] or KBe 2 BO 3 F 2 (KBBF). 19 This method has the advantage of using phase matching to achieve high energy and momentum resolution, 20 comparable to synchrotron-based ARPES setups. However, the photon energy is limited to ≤7 eV, thereby limiting access to large in-plane momenta and preventing access to the full Brillouin zone in most materials.…”

“…44,45 We choose ZrSiS to demonstrate the capabilities of the HHG-based trARPES setup due to the characteristic linearly dispersive states located near the edge of the Brillouin zone. In comparison with laser-based trARPES setups, [14][15][16][17][18][19] the high photon energy available from HHG allows us to access both higher binding energies and larger transverse momentum. This is due to the fact that the parallel momentum can be approximated as k ∥ = √ 2meE kin sin θ/ ̵ h, where me is the electron mass, E kin and θ are the kinetic energy and emission angle of the emitted photoelectron, respectively, and ̵ h is the reduced Planck's constant.…”