• Kar, S.
• Nair, A. K.

Abstract

<jats:title>Abstract</jats:title><jats:p>The ability to tune and control the magnetic phases of two-dimensional (2D) nanomagnets at room temperature is indispensable for the development of future spintronics and low-dimensional spin circuits. In this work, a first-principles-based investigation combined with a Monte Carlo simulation based on a 2D Ising model is used to investigate the electronic and magnetic behaviour of a recently discovered 2D material, Cr<jats:sub>2</jats:sub>Ge<jats:sub>2</jats:sub>Se<jats:sub>6</jats:sub> over a large range of strain and electric field strength. This material offers ferromagnetic <jats:inline-formula><jats:tex-math><?CDATA ?></jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mo stretchy="false">→</mml:mo></mml:math><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="dabc64cieqn1.gif" xlink:type="simple" /></jats:inline-formula> antiferromagnetic and semiconductor <jats:inline-formula><jats:tex-math><?CDATA ?></jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mo stretchy="false">→</mml:mo></mml:math><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="dabc64cieqn2.gif" xlink:type="simple" /></jats:inline-formula> metallic phase transitions in different regimes. In the presence of strain, a colossal enhancement of the critical temperature (<jats:italic>T</jats:italic><jats:sub><jats:italic>c</jats:italic></jats:sub>) is observed, from 149 K to 885 K. The application of an electric field allows a further enhancement of the <jats:italic>T</jats:italic><jats:sub><jats:italic>c</jats:italic></jats:sub> to a value of 919 K, offering a supreme enhancement (~517%), compared to its natural condition. The origin of this behavior can be traced to a super-exchange interaction between the Cr and Se atoms and the intrinsic magnetic anisotropy of Cr<jats:sub>2</jats:sub>Ge<jats:sub>2</jats:sub>Se<jats:sub>6</jats:sub>. The presence of external stimuli engenders spontaneous symmetry breaking with an enhanced magnetic moment (~4.36 <jats:inline-formula><jats:tex-math><?CDATA ${B}$?></jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msub><mml:mi>μ</mml:mi><mml:mrow><mml:mtext>B</mml:mtext></mml:mrow></mml:msub></mml:math><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="dabc64cieqn3.gif" xlink:type="simple" /></jats:inline-formula>/Cr atom), a significant intrinsic spin polarisation (~100%) in a half-metallic regime, and a very high critical temperature. The insights of the current investigation could be useful for future developments in multi-stimuli-assisted room-temperature ferromagnetism and electronic phase control, which are of great significance for future magneto-electronic applications.</jats:p>

Topics

• impedance spectroscopy
• phase
• simulation
• semiconductor
• strength
• phase transition
• two-dimensional
• critical temperature