Abstract
Some single-crystalline materials present an electrical resistivity which decreases between room temperature and low temperatures at zero magnetic field as in a good metal and switches to a nearly semiconductinglike behavior at low temperatures with the application of a magnetic field. Often, this is accompanied by a huge and nonsaturating linear magnetoresistance which remains difficult to explain. Here we present a systematic study of the magnetoresistance in single-crystal $\gamma$-PtBi$_2$. We observe that the angle between the magnetic field and the crystalline $c$ axis fundamentally changes the magnetoresistance, going from a saturating to a nonsaturating magnetic field dependence. In between, there is one specific angle where the magnetoresistance is perfectly linear with the magnetic field. We show that the linear dependence of the nonsaturating magnetoresistance is due to the formation of open orbits in the Fermi surface of $\gamma$-PtBi$_2$.
Highlights
Some single-crystalline materials present an electrical resistivity which decreases between room temperature and low temperatures at zero magnetic field as in a good metal and switches to a nearly semiconductinglike behavior at low temperatures with the application of a magnetic field
We show that such a linear MR appears at a specific angle in the presence of open orbits
The linear MR cannot be obtained without taking into account the open orbits (δ term), and the MR would show a clear saturation at high fields due to an inexact compensation between the electron and the hole carrier numbers
Summary
Some single-crystalline materials present an electrical resistivity which decreases between room temperature and low temperatures at zero magnetic field as in a good metal and switches to a nearly semiconductinglike behavior at low temperatures with the application of a magnetic field. When considering nearly free electrons, the simplest magnetic-field dependence found for the magnetoresistance is quadratic ρ(B) ∝ B2, obeying Electronic band-structure calculations [23,24] show that this compound has a Fermi surface containing multiple electron and hole sheets.
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