Compensated Semimetal LaSb with Unsaturated Magnetoresistance

Area of Science:

• Condensed matter physics
• Materials science
• Quantum phenomena

Background:

• Extremely large magnetoresistance (XMR) is a phenomenon observed in certain materials, characterized by a dramatic increase in electrical resistance under a magnetic field.
• Understanding the electronic structure of materials exhibiting XMR is crucial for exploring potential applications in electronics and spintronics.

Purpose of the Study:

• To comprehensively investigate the electronic structure of lanthanum antimonide (LaSb).
• To elucidate the origin of the near-quadratic extremely large magnetoresistance (XMR) observed in LaSb.
• To compare the electronic properties of LaSb with known topological semimetals.

Main Methods:

• Angle-resolved photoemission spectroscopy (ARPES) to probe the electronic band structure.
• Quantum oscillation measurements to determine Fermi surface properties.
• Theoretical calculations of electronic band structure and Fermi surfaces.

Main Results:

• LaSb exhibits near-quadratic XMR without saturation up to 40 T.
• Resolved spherical and intersecting-ellipsoidal hole Fermi surfaces at the Brillouin zone center (Γ).
• Resolved ellipsoidal electron Fermi surfaces at the Brillouin zone boundary (X).
• Perfect compensation between hole and electron carriers, independent of temperature.
• LaSb is topologically trivial but shares bulk electronic structure similarities with Weyl semimetals like TaAs.

Conclusions:

• The compensated carrier concentrations in LaSb are a key factor for its observed XMR.
• The electronic structure of LaSb provides insights into the mechanisms behind XMR in semimetals.
• Despite being topologically trivial, LaSb's electronic properties offer a unique platform for studying magnetoresistance phenomena.