[Quantum] Many-body Physics

at the [Nano]scale

Homepage of Dr. Angelo Valli

Welcome to Quantum Nano (Qnano) my personal homepage!
I am a Senior PostDoc Researcher at Budapest University of Technology and Economics (BME) in the department of Theoretical Physics.

My research "lives" on the edge between theoretical physics / strongly correlated systems and computational chemistry / nanotechnology.

Learn more about my research and browse my publications. Do not hesitate to contact me.

A general-ground introduction

Nanotechnology is the manipulation of matter on the scale of individual atoms and molecules. Achieving such control requires understanding the nature of the fundamental constituents of matter and their interactions. Remarkably, the laws of physics at the nanoscale are different from what our natural intuition may suggest because both individual and collective behavior is dominated by quantum mechanical effects

The tremendous development in the vast field of traditional semiconductor electronics (i.e., based on Si) has been following the empirical Moore's Law for over four decades. It eventually reached a stage where below a critical threshold (arguably at about ~20 nm) further size shrinking of transistors yields a marginally better performance, while rising issues connected to energy efficiency (e.g., power consumption, dissipation, and leakage). This scenario calls for another technological revolution.

A possible route consists of identifying alternative suitable materials to achieve better performance: C in all its allotropes displays a wide range of properties that make it a natural candidate for post-Si technologies, and it is also relevant from an environmental-friendly point of view. Other less obvious elements, such as  Ge or Te revealed to be promising for, e.g., spintronic applications. At the same time, unraveling novel mechanisms is of pivotal importance to realize functional devices with tunable properties designed for targeted applications

In this framework, my research focuses on the theoretical description of quantum many-body effects in low-dimensional systems, including also molecules to nanostructured materials. The presence of competing energy scales gives rise to complex collective behavior and results in a plethora of fascinating physical phenomena, ranging from magnetism to superconductivity. Furthermore, electronic correlations make materials highly susceptible to external stimuli, meaning that weak perturbations (i.e., variation of control parameters) can result in a dramatic electronic response — which is a desirable property for devices. Hence, besides being interesting for fundamental research, the ability to harness the electron charge and spin as well as to tailor the physical and chemical properties of materials at the nanoscale holds great potential for future technologies.

Due to its intrinsic multi-disciplinary character, my research naturally spans different aspects of physics, material science, and chemistry.